The Chevy grill should fit. I would continue looking for the GMC grill though. Swap Meets, Internet search, e-bay etc etc.
I have a '65 GMC grill. It has no dents but does have some small pitted places near the bottom. It is complete with headlight bezels and mounting brackets. $50 + shipping. I am in north Alabama. Joshua Quillen jjsquillen@aol.com