You need to mill the valve on-off recess in order to use the ULT in Classic RT. The ULT will not fit otherwise, due to the depth of the hole and the length of the ULT on-off assembly. You can't just turn down the end of the ULT, because the outer oring still needs to be there. It would be milled off if you turned the top end of the ULT down. There isn't enough metal to mill an outer oring recess farther down on the top section of the ULT.
Except for the Automag in front, its usually the man behind the equipment that counts.