That dosen't matter! I'm sure that it won't cause any trouble, just label it as such:
[scrolling]THIS IS A BETA THIS IS A BETA THIS IS A BETA THIS IS A BETA[/scrolling]
(C) James.Denholm
Anyway, any idiot can then see that it's a beta, no probs! I'm sure that there has been other public betas hosted on the Hangar.
People will update when they see that there's a 1.0, so I wouldn't worry about giving them a "good" version.
And remember, if you want it not to be public, or are still worried about giving them a "good" version, password the zip/rar and only give the password to the beta testers. Make sure to say "THIS IS PASSWORDED" in the description, though.