Question: When was the trademark established for the manufacturing that occurred starting in 1990 at Spring Hill Manufacturing?

Context articles: Saturn Corporation
Spring Hill Manufacturing
Spring Hill–City View (Pittsburgh)
Spring Hill Nurseries
GM Ecotec engine
Spring Hill, East Cowes
Spring Hill Presbyterian Church
Spring Hill Cemetery Historic District
The Advertiser News
Cadillac XT5

The Saturn Corporation, also known as Saturn LLC, is a registered trademark established on January 7, 1985, as a subsidiary of General Motors.
 The company marketed itself as a "different kind of car company" and operated somewhat independently from its parent company for a time with its own assembly plant in Spring Hill, Tennessee; unique models; and a separate retailer network, and was GM's attempt to compete with Japanese automakers.
Spring Hill Manufacturing is a General Motors factory in Spring Hill, Tennessee.
 It opened in 1990 as the site for Saturn manufacturing and continued through March 2004 as the sole manufacturing plant overseen by the Saturn subsidiary.
 After the United Auto Workers ratified a new contract in March 2004, the plant became part of General Motors, but Saturn-only manufacturing lines continued until March 2007.
 The facility includes a four-cylinder engine assembly plant, auto assembly plant, paint and plastics plant, a Saturn parts warehouse, and a visitors center.
 In 2005, the plant had a yearly production of 198,142 vehicles.
 Harbour Consulting rated the Ion line as the tenth most efficient auto plant in North America in 2006.
Spring Hill is a neighborhood on Pittsburgh, Pennsylvania's North Side.
 Spring Hill was named for the abundance of springs near the site.
 According to a 1977 Neighborhood Atlas, "Germans immigrated there from 1850 to 1920, giving the neighborhood a Bavarian atmosphere.
 Local street names include Rhine, Woessner, Haslage, Zoller and Goehring.
 In 1959 ACTION-Housing opened Spring Hill Gardens, a moderate rent, racially integrated, 209-unit apartment project at Buente and Rhine Streets.
 Spring Hill Gardens was Pittsburgh's first multi-family housing project backed by the Federal Housing Authority."
Spring Hill Nurseries is a mail-order garden center based in Tipp City, Ohio.
 Founded in 1849, Spring Hill Nurseries is one of the oldest gardening companies in the United States.
 The company specializes in garden plants, garden designs, perennials, shrubs, ground covers and gardening supplies.
 Spring Hill distributes catalogs nationwide and maintains a substantial presence online.
 One of the largest companies in the gardening industry, Spring Hill Nurseries’ headquarters features many acres of greenhouses and trial gardens.
The GM Ecotec engine, also known by its codename L850, is a family of all-aluminium inline-four engines, displacing between 2.0 and 2.5 litres.
 While these engines were based on the GM Family II engine, the architecture was substantially re-engineered for the new Ecotec application produced since 2000.
 This engine family replaced the GM Family II engine, the GM 122 engine, the Saab H engine, and the Quad 4 engine.
 It is manufactured in multiple locations, to include Spring Hill Manufacturing, in Spring Hill, Tennessee.
Spring Hill, East Cowes is an estate on the Isle of Wight, England, the centre-piece of which is the large landmark manor house of the same name.
 It was to become the family home of the Shedden family.
 The estate is ideally placed, having sweeping views over The Solent.
 It currently occupies 22 acres, although in years gone by, it was much bigger, probably amounting to around 100 acres.
 However, even today, it still encompasses Spring Hill House, a farmhouse, farm cottage, a gatehouse, one other large residence and around half a dozen fields.
 From the 1800s, East Cowes contained four prominent estates, with Spring Hill being amongst the first of them to be built.
 Spring Hill lay between East Cowes Castle and Norris Castle, with Osborne House, the country estate of Queen Victoria, close by.
First Presbyterian Church of Spring Hill (The New School Presbyterian Church at Spring Hill) is a historic church on S. Main Street in Spring Hill, Tennessee.
Spring Hill Cemetery Historic District is a national historic district located at Charleston, West Virginia.
 The district is a 172 acre site located on a series of tree shaded and landscaped hills overlooking central Charleston and includes the following cemeteries: Spring Hill Cemetery (established 1869), Mountain View Cemetery, B'nai Israel Cemetery, Lowenstein Cemetery, and Mount Olivet Cemetery.
 It is West Virginia's largest cemetery complex.
 The district features Spring Hill Mausoleum, a stone faced reinforced concrete structure constructed in 1910.
 It includes the graves of West Virginia Governors William A. MacCorkle (1857-1930) and George W. Atkinson (1845-1925).
The The Advertiser News is a weekly newspaper in Spring Hill, Tennessee.
 It is owned and published by GateHouse Media Inc..
 The newspaper is published once a week, every Wednesday.
 Its Newspaper Designated Market (N.D.M.) stretches into two cities in two separate counties in Middle Tennessee.
 It is primarily distributed to zip code 37174 Spring Hill (both the Maury County, Tennessee side and the Williamson County, Tennessee side and zip code 37179 Thompson's Station, Tennessee.
 It is a Total Market Coverage "(T.M.C.)" paper and is delivered to 99% of all deliverable mailing addresses in those zip codes.
 It is the only newspaper that reaches both sides of Spring Hill with full saturation.
 Two daily papers are distributed in Spring Hill but one primarily on the Williamson County side and one primarily on the Maury County side.
The Cadillac XT5 (short for Crossover Touring 5) is a mid-size luxury crossover SUV manufactured by General Motors.
 It was introduced at both the Dubai Motor Show and LA Auto Show in November 2015.
 The XT5 replaced the Cadillac SRX crossover when it was launched in spring 2016.
 It is the second model to use Cadillac's new alphanumeric naming scheme (after the CT6) and the first in the Crossover Touring (XT) series.
 The XT5 is manufactured at GM's Spring Hill Manufacturing plant.
 The Chinese-market XT5 is manufactured in Shanghai by SAIC-GM.