Wheel Date Code

My fender tag says 510. My car is a 70 so it was born on 5/10 of 71. Is it possible to have at least one wheel dated 5/26 of 71? I have only checked one other wheel and it's dated 4/26 of 71. Will check the other two later.
I'm all screwed up. None of my wheels are date correct. My car was built in May of 70. My wheels are dated 71. The ones I have checked anyways.