Just be sure they fit well. The packaging warns you that there's some variation in grip frames, and so one size does not necessarily fit all... at least, not perfectly. I've handled more than one square butt S&W wearing Pachmayrs that wobbled back and forth just a bit because of this, and no amount of screw tightening immobilizes them. It didn't interfere with handling or shooting, but it does put the finish at risk.
A little wobble, a little grit under the rubber, and voila: a ruined finish. I've got a M58 in the re-blue bin at the factory right now, because when I took the previous owner's Pachmayr Signatures off, I found they'd ground a bright arc of white metal underneath. I rather suppose this problem isn't peculiar to the Pachmayr brand, either.