I have no experience with auto lockers but I notice on the Lowrange Offroad site that the mini spool for the rear of a Samurai and a Kick are the same item but the auto lockers have different part numbers. The reason I'm asking is that I have a rear Samurai auto locker but I will be changing to the larger Kick R&P in the rear and I had hoped to still have been able to use the auto locker from the Samurai. What is the difference and can it be altered to suit?

I think it should be the same, call trail tough.

I believe they are interchangeable. 

I've used a sammy locker in a kick rear.

I've used a sammy locker in a kick rear.

That's what I want to hear  but I wonder why they give them different part numbers 

I believe there is a slight difference in the side gear design.  But not enough that they are not swappable.