Recommending gbp is like sending a friend to a hooker who is known to have the clap.... something you just don't do.
BBB website shows 13 complaints. Most appeared to revolve around "supply chain" issues and some level of courtesy/honesty by their phone reps. They did have lengthy responses to all of the complaints and some of them showed that the issues were resolved. Either with items finally delivered or a refund issued. So at least they are aware of the complaints and were responding to them. In good faith? Have no idea.
Have never done business with them, they did have a multi page spread feature story (not an ad) in one of the final print issues of "car craft" magazine, that showed their personal wrecking yard with multiple carcasses. Whether those carcasses still exist, three/four years later is a good question. MIght be an option, if OP can travel to that site in person, and inspect doors in person, instead of relying on electronic transmissions. Would suspect said doors, if they still exist, will be on the high side price wise. I have not seen many two door A/G coupes in the yards, down here in El Paso, they have pretty much dried up. Ironically, the two I have seen, in last 3-4 years have been earlier (78-80) versions, probably due to the fact greater numbers were produced before 81. 82-87 coupes in last ten years? Pretty much nothing. Probably due to the fact they were hoarded by lowrider types for spare parts.