RE: Red Golbat [Blue Version]
I've had something like this, though it was when my friend was playing a new game on my Emerald. Around the rival battle, he came across a pink Poochyena. Since then, we've checked to make sure it wasn't shiny, and to this day, we have no idea what happened. Sadly, since it was around the rival battle, he didn't have any Poké Balls. Even if he had, he wouldn't have been able to save, as this new game was just for fun and was not going to be saved over my original. And because we had no access to a camera, we couldn't take a picture or anything.
Anyway, I halfway suspect that this and your red Golbat are possibly extremely rare programming errors. Since you're saying the Golbat was red, we can assume that you were playing on a Game Boy Color, Super Game Boy, Game Boy Advance, etcetera. Also, since normal pre Game Boy Color games could only display 4 shades of gray, (Or four shades of blue in color. I can't remember, were more than four shades ever shown?) did you ever notice any discoloring?