Yeah, these will be the same assembly one to the next, the 930 receiver is the same on the SPX as it is on other 930 models. As far as I know, the forend length is identical so the gas seal (if thats the proper term?) should mate up. I've been told by Mossberg some failure to feed issues come from the gas seal not being lubricated properly when parts are swapped out, I cant testify to this being accurate, another member or 2 may be able to give you better info. If thats true, it may be something to pay attention to if you swap the forends.
Admittedly, this is an area I'm not well versed in.