I don't think so... thing about GMCs as you probably have found is that although you can find Chev parts all day and night, few GMC parts are reproduced. Someone had done the same to my '59... removed the ashtray and cut out a larger radio opening, then cut out the original radio opening and crammed the ashtray back in... best bet is to cut your own patch panel from a virgin dash out of a salvage yard, or post an ad under "Parts Wanted" and see if someone can cut you that piece.
