67 barracuda numbers

Hi, I have read numerous articles about vin and fender tags. How can you tell if the vin and fender tag are legitimate? The car in question is a 67 Baracuda Formula S with a 383. The vin and fender tag go together and the last 5 numbers on the radiator support match the last 5 on the fender tag. The support shows no sign that it is re-welded as the factory spot welds are still there. The factory torque boxes are there on the shell. My question is that I am finding yellow paint under door plugs latch plates and inside the door - the fender tag says it is supposed to be the dark green GG1 which the car is painted now. Is there any other way besides the radiator support to check if the shell is the matches the fender tag? Thanks for any help, Dan