Well, you can try. This is a big, expensive project though. I mean if you don't have the aluminum stock of this size lying around, then buying that alone can cost you a bundle. The G540 is only $299 here, and it's excellent in many ways OTHER than just resonance suppression. There's like half a dozen reasons that could come up that'll make you want to replace an obsolete controller like this. The only reason to go with it would be if you already HAD a fully working HobbyCNC controller, power supply, and case built that you got with the mill and want to make it work better with dampers. If you're gonna buy a controller, where you have a choice, don't buy that one.
Actually I had a couple of dampener ideas:
1. Mine came with hollow knobs. The interior had 3 ribs which separated the interior into 3 chambers. By filling each about 2/3rds full of lead bird shot (cut open some shotgun shells, carefully), cover with a rubber pad then a plate of acrylic, it could be a fine damper.
2. Sorbathane urethane pad. That stuff can be really good. If you cut an interior wheel with a set screw, a spacing for the Sorbathane pad to be wrapped around, then an outer mass with handle knurlings, and proper compression holding it together, it should be a fine damper. Less noisy too.