The spring axles are knocked in (splined on end with a threaded socket) – you would have to tap them out and replace the spring and then tap them back in to the body – never done it myself – mine were rattley on my XE’s (very old) and I did up the tension screw to max and this helped the rattle.
I think the trouble with the Rocs (as they are cheaper) is they are not designed to have the springs replaced? IIRC the std ATACs are?
Otherwise can you pack out the spring axle with a circlip of similar to take up the lateral play?