MkIII Volthane grip on Ruger MkII?

I have three Ruger MkII pistols. The oldest has a Volthane grip that I bought when they were still available from Volquartsen. Last year, I put an Altamont thumbrest grip on the newest (to me) gun, but I hate it. I may take a rasp to it to reshape it, but if that doesn't work out, I'd be happier with Volthanes on all three.

There don't seem to be any MkII grips on ebay, but plenty of MkIII models. Can the MkIII grip be trimmed, if needed, for the heel magazine release? Any other fit problems that I'm not anticipating?

The unoccupied magazine release hole is of no concern to me. Just want to check that it will otherwise fit, and that trimming a little around the heel (if needed) won't cause it to fall apart.

My understanding was that the changes between the MkII and MkIII were limited to moving the mag release and adding a magazine disconnect safety, but maybe there are others I don't know about? My guess was neither of those would prevent the grip from working on a MkII, but I'm hoping not to find out the hard way.

No way to know if any changes they made to the mold when switching models will be better or worse for my hand since the only Volthane grip I've ever seen in the wild is the one I own. The MkII Volthane is nice but I wouldn't say it's perfect, so it could go either way. A fully custom grip would probably (hopefully!) be better, but the Volthanes are very convenient since they require no pre-planning to order.