ALL of this information MAY be accurate, or it may be rife with errors. It is only as reliable as the person who gave it. For that reason, you should plan to use what you obtain from the funeral file as a guide to further research. There may also be details about the location of the grave and the type of monument or marker. Your unexpected appearance at the funeral home office demanding to see funeral records from decades ago would likely kill your chances of EVER getting the information.
Many funeral homes keep recent records in file folders in cabinets easily accessible to the staff.
These are usually kept alphabetically by year. Others use bound funeral record books, in which the records are entered chronologically, with pertinent papers kept separately. Seldom is an index maintained, so knowing the year of death is usually required. Even when there is an index, it may be incomplete due to clerical oversights in entering names over the years. As a practical matter, they are then very difficult to retrieve.