Right. You can use the old MIc buildings - that's ok. Especially if you choose a type3 or type4, obviously they would still use their MIC to train their troops there. If you take the time to build a type2 or 1, it's assumed they've done other things to install their government choice there, not just build one single govt building over 20 turns (), so we think it's ok then to just keep the MIC the same too.

No one should expect, currently, to be able to train much of anything inside central Italy for now, unless you're roman. Just raze it and move on.