I believe the date 5-5-1966 is when that BC was issued, probably needed for entry into kindergarten. One might have been issued at DOB but misplaced and thus another replacement one made.
Exactly, and that date was on the bottom of the copy, along with the seal, which indicates that it is a certified copy. It's not on the part that is a copy of the original. That's the way it was done, BC, before computers, and "AM", after microfilm. Before microfilm, you might get a handwritten or typed abstract, sort of like the computer generated abstract of these AC, after computer, days. Many states are now, or have plans to, go to just digitizing the whole original, as well as entering the data from it into a database. That way it's searchble, but when you need a copy, you get a copy, not an abstract, computer generated or not.