Cam, you are a better man than I. I always appreciate that!
As for your question, I do believe it should go right up. I recall having a rear wheel from a 1989 KX125 and it fit right up to my KX500 (used it for a paddle tire). I never ran it due to the smaller size rim, but it did line up perfectly and sold it to somebody who was wanting to use it for their KX500. I think it is the same as a 88.