Serial Number..

I know you can pick your own serial number, but.......

Does it have to be all numeric?

If not all numeric, is it just letters and numbers?

Or can you use special characters or dashes or underscore ?


thanks

Just a wild guess, but...being a government agency, I'm thinking they'd limit it to letters and numbers, no special characters.

I can see having no special characters, but "-" is often used. (Air Force used to, may still be doing it.......)