I think they are in Data_Source already. Please check that before adding them to Master (i think there was a reason Why Not ever Model was added to Master)
Sorry, I was not aware of that as switching the branch to data_source produces strange errors here...
I wanted to use those on various maps, that is why I added them to master.
Unfortunately importing .md3s seems to be buggy, not only in UFORadiant, but also in UFO-AI, so maybe I should revert this commit