Hi GaryZ,
Welcome to the Heartland Owners Forum.
I'm afraid the factory won't be able to help you on this question. The Heartland RV company started in 2004, long after your 1992 Prowler was built. Heartland recently purchased the rights to the Prowler name, but probably doesn't have much, if any, product history.
There's a small chance another forum member might have had a Prowler from the early 90s and might know something that would be helpful to you.