Welcome to the forum and congratulations on your "new" GMC. There are a lot of similarities between the GMC and Chevy but there are distinct differences in the areas of engine, front sheet metal (hood & grill) and paint colors and pin striping. As you can tell from the response in one of your other posts, the GMC engine is longer than the Chevy engines and will not fit in a GMC without modification. You may want to visit the Old GMC Trucks forum board and use the search function to answer some of your questions and help locate any GMC specific parts. Here is a link to it.
OldGMCtrucks Under the technical section of that forum is information on some of the paint questions you have. Good luck with your project.
