Just from my limited knowledge I have tried to obtain about my Sustainer.
I own an early one.
Early ones were very basic in appearance and have no binding on the neck. Only binding on the head stock. Dot inlays on the fret board, Kramer name on 12th fret.
They had no battery compartment. The 2 batteries were located in the electronics cavity. They had one red LED light to indicate when the battery was low. I think the early ones all will work if they are turned on without being plugged in, resulting in a dead battery in a day. Maybe they changed this? I remember when they were new, music stores would demo them that way.
Early color options were Black, Red, Blue, and White.
Later the claws would show up as an option on fret boards.
Binding would be on the side of the fret board.
Then the battery routing behind the tremolo cavity, along with the green LED indicator (on) light. More color options.
There are 2 types of circuit boards. Early and Late. The blue prints are on vintagekramer.
As usual you cant rely on Kramer serial numbers to date a time frame.
These pic's are from when I first bought it. This guitar sounds AWESOME with a Duncan 78 custom trembucker now in it.