As I recall, they're the same inerds except for the output shaft and it seems that some of the gear boxes had needle bearings on the reverse idle gear vs a brass bushing on others. (Or was that on the Jeep I owned??) Get another vote on this before tearing into it. It's been too many years since I was in one.

Anyway, when swapping in used parts like that, you would want to bring as many of the components over together that are already worn-in together. Of course matching them to a different output shaft may result in a slight whining in first, second, and third - but then again maybe not. And so what if it whines a little. Just turn the radio up.