Well, technically, yes, you don't have to do a full rebuild (assuming the other parts are operable/working). But if you (or someone else) is taking the time to replace the fork, you may as well consider rebuilding it, especially if the car is higher mileage. One other thing too, that I would reccomend, is to get it replaced ASAP. The longer you try to drive with a broken shift fork (if that is the problem), you'll have a higher chance of ruining other parts and being forced to do a rebuild or swap. I'd just pray that if the shift fork broke, it broke cleanly and didn't shatter chunks/fragments/flakes all over the place.

Yes, our trannies suck ass. Hence the reason why I try to baby my car, even when getting on it. Good news is, the forks are relatively inexpensive, even from Satan. Try to get your hands on something other than the aluminum ones though. The EVO forks are pretty popular and hold up well.

My opinion, if you like to drive your vehicle hard frequently, you may want to opt for a rebuild and double up on the 2nd synchro while you're at it. Jerry will probably do a rebuild for a decent price though. If you have a nice chunk of cash laying around, then you can send it to TRE. If you can't afford it though, then that's understandable. Anywho, just remember to take care when ragging on your vehicle.