Common AN470/426 AD-- -- rivets, the ones with the dimple should be ok even after many years.
I remember that years ago there used to be what was known as "refrigerator rivets" that had to be kept in cold storage until they were shot. They would definately age harden if not kept cold. Can't remember the alloy or nomenclature but they were not "AD" rivets with the dimple. (These may have been what you had from Boeing, David.)
Someone with up to date knowledge or reference material correct me if i'm wrong.