Looks as if Gulfstream only manufactures towables now, however they may have information on class A coach parts in their archives. If all else fails you might try giving them a call.
Good luck and let us know how you make out...
Jim & Sherry Seward
Las Vegas, NV
2000 Residency 3790 V-10 w/tags & Banks System
2003 Suzuki XL/7 toad