Doom version on print?!

[Hartung]

Hello Doomers - new fella' here so please don't rip and tear me..!

I have been wondering for some time now - i really hope some of you guys can help or at least just clarify a bit.
Some of the floppy versions of Doom have the version number printed on them, say, 1.1 or 1.2 - you all know..
Well, some floppy versions DON'T have the number printed on the floppy disc label!
Question is: Is there any reason why some have when others don't? Did ID just apply that randomly or did they apply it after a certain amount of time for releases?

I have been searching this thing called the internet all over the place for getting some clue.
If this is already clarified on this very page i am deeply sorry for not having a proper set of eyes and wasting
you guys time.

Rip and tear!

Ben.

[Technician]

I'm going to make the assumption that they weren't anal retentive enough to update their labels when they updated their game.