A&I Products Seat, BLK Parts. Replacement for John Deere Part Number GY20063 All parts come with a 1 year manufacturer's warranty from A&I Products. We are an official dealer of A&I Products. $9.95 FLAT RATE SHIPPING - NO MATTER WHAT OR HOW MUCH YOU ORDER!!! Seat Mounting Hardware: The OEM applications that used this seat might have used either SAE or Metric mounting bolts. This replacement seat uses only SAE bolts. Do not reuse original Metric bolts. Damage to the threaded inserts will occur. As this bulletin covers many different part numbers of seats, you will need to determine exactly what size bolts your specific seat and application will need. The threads will either be 5/16-18, or 3/8-16 and some seats could use either depending on which mounting bolt pattern used.