I think everyone covered it?
The input spline count change over was between the '66 anf '67 model year.
The 70 and earlier transmissions used a front pump with just a metal shield covering the vent. The later pump has a plastic baffel. The stator support (bolts to back of pump, and fit into the front drum) is different because the front clutch drum used a wider bushing from '71 and up.
The front servo is slightly different. The early servo uses a smaller diameter pushrod, and the later servo uses a load controlled / larger diameter pushrod. The rear diaphram spring is different, The later valve bodies usually have the part throttle kick down assembly. I don't know the year when they changed the governor design that has the small cone filter in it?
I'm sure there are a few other changes, but I doubt it would affect the rebuild kit selection.
I think all the aftermarket front drums require the use of the newer style stator support (That is normally on the newer style pump.)
At least it is not a pre '66 model with the rear pump and cable shift / park setup