I don't have a MK III, but I have FOUR Ruger MK II's. There is no problem in disasembling them for cleaning, and reasembling them. If I can do it, anybody can do it. One only needs to know how to read the manual the first few times. It is ridiculous to say that this is an issue.
I say find a used MK II, or get a MK III and take out the mag disconnect and LCI.