Turns out this may not be as difficult as you would guess.
The glass was likely supplied by Guardian Industries, 2300 Harmon Rd, Auburn Hill, MI 48326. Phone:800-327-5888, website http://www.guardian.com
Go to http://www.rvglassparts.com/yearMakeSearchAction.do
to fill out a form to get your quote. You only need the VIN, the month of manufacture, & the serial number of your 1994 Gulf Stream Sunsport.
Let us know if this works out for you.