I just made an interesting discovery. So I have a milled down chrome RM2 on one of my oldest Mini, still has all original everything, and using a fatter than I need o-ring under base to hide the brass, not to adjust where the cap hole is (but the hole is on the wrong side necessitating me to use my thumb instead of index finger to fire... My thumb is not happy about that.). So the coil I did for it today is 1.83 ohm. It needs to be just a hair less ohms. So when I got home just now, I took a chrome, non-milled RM2 off of my Mini 2.0, one of the first productions, not the 2.1 with bigger well, but does fit and work well on 2.0, to see if its hole would line up on side away from me on 1.0....... low and behold the RM2 that fits the Mini 2.0 does not fit and fire in Mini 1.0. Remember it is not milled down. I haven't tried it on any of my other older Mini yet. But it is interesting. So I put the 1.83 back on the Mini 1.0 and now the hole is away from me and firing well. Interesting.
So if you happen to have a non milled RM2 and a Mini 2.0 it just might fit. Give it a try.
BTW... I'm holding out on doing a rebuild on this old Mini 1.0 as it doesn't need it. It's been in constant use over 2 years. If I did rebuild it would probably raise the center post a bit, though.
Feisty Alice