My MVS boxes don't have serial numbers...is this unusual?

I just noticed that my MVS box labels don't have serial numbers on them. Is this rare?

I found 6 of them when I bought a 6-slot cabinet at an auction two weeks ago. They were all stacked at the bottom - all old titles, so I'm guessing they came with the cabinet.

Many old titles didn't have serials.

Some new doesn't have either. Check a thred called MVS serial/physics in the tech forum. You might find some help there.