I think any 135 can flash to IKM0S without much trouble. The only reason that method worked on his 3 seems to be because the MSD81 he used originally came out of a 135, a basic fact I didn't see explicitly stated anywhere, but might've missed.
It doesn't work his way on a DME originally from a non-1 series. It's not just software, there are things stored in non-volatile areas that don't change. Without some work, seems DME will always see what it came from/thinks it's in and recognize roms accordingly.
Easiest solution (i.e. without Jake's help) on non-1 series seems to be exactly what he did, drop in 135/1M DME, rekey and, if needed, flash IKM0S/disable checks.