i would say definatley not, it all depends on how the person was raised. I grew up on an acreage so I never got to play with friends as much as other city kids therefor I was declared anti-social. I still talked but I'm really shy to this day still just because I'm not used to be around people 24/7. a few guys have told me that they think I'm decent looking, so no I don't think all anti-social people are ugly .
Ugly? No, that's not a factor in being antisocial. Unattractive? Possibly.
Being antisocial usually means that you're harder to approach, you don't make as good of an impression on people, and you're not as easy to talk to in general. Such traits could make for someone not being attractive, but that doesn't make them physically ugly.