I've looked at the Abobo sprite for a long time and I never thought about this. I mean, I always thought it was just a frown. I guess it does look like a mustache. I wish I wasn't reminded of that awful "Double Dragon" movie. Abobo was the worst thing about it! He was my favorite character!
Admittedly, I'm not a fan of the games. I just know him. The animation here was great. Yeah, the Big Adventure game was fantastic too. I'll go with the mustache.