There is a good chance it was Kwikee but they have changed over the years and the part may not be available from them any longer. You could try a RV salvage yard that may have what you are looking for. Take a photo of the cover and send it in emails to prospective suppliers and see if you can't locate one. Good luck and keep us posted.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7