I would hope that any new pistons that are being supplied by a VW Group source, will only be the latest version for that engine, maybe talk to your engine builder/repairer about the oil sprayers etc mentioned elsewhere, it would have been good to find a complete "best rebuild options" parts list, but I don't think that is available clearly anywhere, I think that someone in Italy even replaced the chain drive etc with parts not intended for the CAVE engine, but he was doing some of the work himself so time and modifying existing parts to accept the parts for the later engine was not a
problem when his intention was to make his CAVE as reliably as it should have been when launched.
Remember all the other actions that should be taken during an engine rebuild, ie listed in the "Lucifer's
guide" and any other sources of good advice for this engine.