I have followed several threads on other forums concerning "old" primers and their usefulness. The general opinion is to go right ahead and use them.
I can see what appears to be a stain on the sleeves suggesting some exposure to moisture of some sort at some time. I have been lead to believe, based on other people's experience, that even this makes little difference. Some experimenters have even intentionally soaked primers in various liquids to test the theory and the primers still fired when allowed to completely dry out first. If you have any doubts, load them for "practice only" ammo.
I still have some from that era and they are working fine and would trust my life with them! It is best to keep primers and ammunition in a cool dry place.
Primer mixtures are packed in the cups wet and dried out to be sensitive enough to work. Even if they got damp or wet they will dry out again if kept in a dry place.
Just visually inspect them to see that the compound is still inside the cups. Test them to see if they indeed work.
Bang Bang Bang Bang Bang Bang 'cept for the one or two that you don't seat or put in upside down. Time to thank that man again for all of the fun he just gave you. Might use some thing with a known good history for non-play time though.