I have purchased some NOS items locally and in the lot was a stack of Mustang decals. They include several of the "289 4V", Sprint (silver and blue), tire pressure decals, and one trunk decal for the spare / jack instructions. All are for the 65-66 model year. The reason why I am asking how to differentiate is that this gentleman who had these, (now passed away), was into Mustangs from day one and was an avid member of the MCA to which I even have a vintage MCA window sticker that was in the lot. There are Ford part numbers at the bottom but I'm sure repros can copy that too? Because he hadn't been as active into Mustangs in his later years, I would dare say these would have to be from the late 80's. I'm guessing repros would produced then, and even with the Ford numbers?
I will try and post some pics of these decals tonight.