Like I said if he has no problems and it running fine, no noises from it's output, leave the caps be.
If he really want to make it sing beyond his wildest dreams with a mod, then do the mod I linked to.
And then while the board is out do the caps if he's worried, as it's a pain to get the board out of one of these just to do a cap change and nothing else and maybe for nothing if it's working fine.
Cheers George