On my 99 Dolphin there are 4 screws holding the cover down. Two are on the front upper flange under the dash one in each corner. Also two on the rear flange at floor level in each corner. All are horizontal and as Scooter posted they are hidden by the carpet.
1999 35 ft. Dolphin 5350, F53, Banks System, 5 Stars Tune, Air Lift Air Bags, Koni Shocks, Blue OX TruCenter, TigerTrak track bars F&R, Roadmaster 1-3/4" rear auxiliary sway bar, 2004 F450 Lariat Pickup 6.0 Diesel Crew Cab DRW, 4X4, GVWR 15,000, Front GAWR 6,000, Rear GAWR 11,000, GCWR 26,000,1994 36ft Avion 5er, GVWR 13,700, 2,740 Pin Weight.