KZ1000 police 2001 and 1981 J motor countershaft differences--

I picked up at 81-ish 1000 CSR motor, and noticed the countershafts are different, splines and sprocket bolt v. nut.  Are there any other differences across these motors?  I would like drop this motor in the KZP frame, all else looks intact.  Specifically, is the offset from 1981 CSR front sprocket the same, just that Kawasaki changed the output shaft during the production run?
Any other thoughts? Thanks,

According to the parts diagrams at Partzilla, Kawasaki used both systems on the J-engine Police bikes 1982 through 1986 (KZ1000-P1 through P5), so my guess is that there will be no Fitment problem for you.

The rear coupling assembly and its spacers are also the same.