Gulf Stream, like other RV manufactures, didn't have custom designed mirrors made exclusively for their RVs. They are from one of the mirror makers in the U.S. You might check with GS, even though they don't do Class As anymore, someone should know who the supplier was in 2007.
You could also search your mirror for a brand or number that could give a clue. You mentioned Velvac, a major RV supplier, how about
Rosco or
Lucerix?