Probably aren't quite that old, I think 1972 was the year of the copy write for the red white and blue Mopar label so a lot of labels on NOS parts say 1972.
If the decals aren't pulling away from their backing anywhere you are probably OK.
The guy restoring my T/A had a bad experience using NOS decals on a '69 Mach 1 he restored. I have an NOS set of decals for my car and I don't know if I'll be able to convince him to use my set. I may have to take the car somewhere else to have my decals installed when the time comes, as he seems pretty down on NOS decal sets, and since no one seems to sell a real good repro set, I'm between a rock and a hard place if I want my original set installed!