players numbers on punts

Yup. Same as any other play. You get an illegal formation penalty if there are less than, I think, 7 people on the line at the start of any offensive play.

Cycloptichorn

No I mean numbers on uniforms on LOS

Don't think so, not in the NFL at least. Not sure about that one though.

Cycloptichorn

i know certain positions have number ranges -- ie. wide receivers wear 80's.
but i don't think there are restrictions for special teams, because many players play offense or defense and special teams...

Yup. I guess it's all about how you are reported into the game - for example, you can have certain people catch the ball only if they are designated as receivers, which I think they announce by saying 'so and so is eligible for this play....'

I just realized that I really need to find a good book or two on the history of football, and the NFL.

Cycloptichorn