Sorry if this is a bit of a newb question, but I just need a bit of confusion cleared up.

I've been practicing on accoustic guitar for a few months now, and recently switched to an electric. I purchased a Yamaha Pac-112J, however, while the body is in perfect condition, the neck was damaged significantly during transit, and without freight insurance (gah, I'm a fool, i know), I will need to replace it.

Anyway, am I to assume that all bolt on necks are interchangeable? Or are there specific measurements and whatnot to look out for? Also, before purchasing the guitar, I did try another guitar (A fender of some description, I believe), which featured a reverse headstock, which I personally preferred the look of. Are these hard to come by?
just make sure the neck is the same scale, but im sure you could just get a neck shipped by yamaha.
Yes there are specific measures. The neck pocket being most important. There are at least 2 different sizes in neck pockets, 52mm and 56mm. Easiest way would be if you found another neck from the same model.