Stonehill, do you do re-sleeving? You have loose sleeves in your photos.
By the way, yes, they are not all the same exact design. The 1979 (or was it 80?) rear master cylinder piston was a bit different design than the 1982. Not important, but one had that plastic piece (where the spring goes) and the other didn't. So yes, not all exactly the same, but those I've seen all were the same size inside (diameter). All I've seen were A models.
1982 Kawasaki KZ1300 A4
1981 Kawasaki KZ1300 A3
assembling engine, chassis & electrical from 79 - 89 parts
Seeing as how we're on the subject of rear master cylinders, I've got a new one- assume, for a second, that somebody (me) decided to repaint his MC with caliper paint, and per the instructions cured it at 200 degrees F for an hour.
Now assume they (I) didn't realize that the access hole used to drill the two smaller holes into the bore was sealed by a plastic plug.
Assuming this happened, what would be the best way/material/whatever to seal this?