You'll be better off going with a 250 shock, 500's are sprung and valved for a lot more weight.
Physically, sure they'll fit, and they'll work....but the 500's have less shock travel and different measurements eye to eye.
Theoretically a shock from just about any quad will fit the 250 so long as it'll fit in the shock mount.


Sorry if this might cost you a sale quadman, you can kick me in the kneecap if we ever meet