My recently purchased 66 Beaumont convertible is missing a few letters. I bought the complete set from CPR. My question now, how are the supposed to be fastened? Looks like originally the were pressed in? No idea. There are no mounting studs. Any help is appreciated.

My original ones definitely didn't have speed nuts or studs. The repro ones don't either. Almost looks like lead or some other soft metal was pressed in from behind. I assume some kind of epoxy is the way to go. I should have taken pics. I've owned probably 30 or more classic Pontiacs, but never seen this method before. I fully expected studs and speed nuts, but not the case.

CPR had them, ran about $80 I think. I'm thinking that duplicating the factory method would be impossible. I guess glue it is. Studs and speed nuts would have certainly been a better alternative.

Could also use thin moulding tape. I have used it on alot of vehicles after painting for emblems, there's no mess like with glue ( doesn't spit out the side) and it sticks like crazzy. Put exposed sticky side to back of letter, then use a good sharpe razor knife to cut along the edge of letter so there is no tape exposed. Remove layer of protective cover and put a piece of wax paper between letter and where you want it placed,the wax paper keeps it from sticking in the wrong location and won't bond to the tape. Once you have it in place slowly slide out the wax paper and press into place as you remove it. Just another option. Most local jobers carry it.
3mcollision.com/products/tapes/attachment-tapes/3m-super-strong-automotive-attachment-tape-03609.html

Good tip with the wax paper Hawkeye.