Let me start by saying that I'm completely clueless when it comes to guitars.
After browsing the forum, I've gathered enough info to settle on buying a 112j, but the problem began when I found the different variants of it.
On the Yamaha website there are 4 colors/finishes listed: black, LB (blue), MR (red) and NAT (wood-ish).
The thing is, I found a few other variants not listed on the site while I was browsing internet stores, namely OVS ("old violin sunburst"), CX BL (entirely black), YNS ("yellow natural satin").
Are colors the only difference between all of these variants?
Also, is there a reason some of them are not included on the Yamaha website?
Dude you are nitpicking over colors. If it had any different specs(electronics/ pickups/ hardware) it wouldn't be a 112j. The only suggestions I'd say is look at the fret boards. Maybe one is rosewood 1 maple? I didn't think Yamaha had male fretnoards but I could be wrong. I know 112s are great beginner guitars. Enjoy!!!
If anything isn't included on the Yamaha website or a reputable website such as Guitar Center, Sam Ash, Musicians Friend, Zzounds, Sweetwater, etc. I'd be leery of it.

The 112j, as far as I know, comes in yellow, black, red or blue. I could be wrong, but those are your guaranteed ones.

Yes, they will have the same specs except color. Any ones that you find other than those 4 could possibly be a mislabeled Yamaha model or a fake.