I recently bought a used Zone VI washer; I think it's representative.
The other shell should have slots for dividers and you should have a divider for each slot. On my Zone VI, the 2 outer dividers (1 on each side) are taller than the other. There are 3 or 4 crosspieces on the bottom that the dividers rest on (on the zone vi, they are removable). There is a plexiglass top that rests on the 2 outer dividers (to keep prints from floating up). That's pretty much it. So I guess the main thing is whether there's a divider for each slot, plus the top.
You'll have an input tube with a fitting (typically female hose) and an output tube. If the washer has a drain, you should have a plug for that drain. If missing, these should be easily sourced.
I agree with tkamiya that the integrity of the shell far outweighs anything else.