Here is what I've found after looking into it.
I talked with Holz about this today as I'm going to be moving one of their Alpha X skids from a friends 2010 155" Dragon to his new PRO-RMK. (the other direction)
My buddy Mike spent good money to get the HRP A-X suspension for his 2010 sled and did not want to give up on the EVOL-X capabilities... and since there are no plans from HRP/Carls (according to HRP) to offer the EVOL-X for the aftermarket as a rear-track shock upgrade for the new Pro RMK he decided he wanted to put the A-X into his PRO because he really liked having the compression adjustment and DSC controls of the X shock.
Also, at this point, HRP does not have an Alpha-X kit for the new sizes of the PRO-RMK shafts etc that would come from the Pro skid... they may offer a hardware kit to make it a bolt in deal though as that is an excellent skid with an Excellent shock and would be an upgrade from the stock PRO suspension.
According to our conversation it will swap over with minimal efforts.
I took the measurements off a show sled with a Starrett tape which confirmed the conversation with HRP. The distance on the RAW and PRO from the front drive shaft to the front swing arm mount in the tunnel are the same. The distance between the front bolt and the rear drop bracket is the same (maybe 0.010" off).
That will not be exactly a bolt in deal, but pretty darn close as all we are talking about is changing fastener sizes.
I'll have to take the cross shafts for the suspension mounting in the tunnel that were installed in his 2010 dragon, drill them for larger 10mm thread-serts for the 4 10mm bolts to bolt the suspension into the PRO RMK tunnel factory bolt hole locations.
NOW..on in the other direction... Putting a PRO-RMK skid into a RAW chassis.
Again, you have to deal with the bolt size difference as the 10mm is just slightly bigger...
Two methods,
1) Drill out the holes in the tunnel and drop bracket for the slightly larger 10mm bolts (which would make them sloppy fit if you decided to go back to the stock Dragon/RMK skid)
2) Drill and install 3/8" NC thread serts into the Pro RMK cross shafts.
If it were me, I'd just drill the holes and then I could Time-sert the stock skid to the 10mm size if I needed to go back to that stock skid in the Dragon.
At that point, it would bolt into the factory skid locations on your tunnel.
Pretty straight fwd, close, but not exactly bolt in.
Also HRP has an excellent revalving program for the Walker Evans shocks on the PRO Skid so you could get it dialed in for your rider weight and style... Bigger springs for the FTS and RTS are available from Polaris, RCS (titanium and Cromo) if you are a big boy or on the light side.
ALL this being said... I have not personally installed or swapped these skids yet.