This mill is a Yuasa/Enshu 3 axis CNC mill with a Fanuc System 3M control? If it is, it will certainly do 3 axis contour milling. Depending on the options in the control it could also do helical milling (milling a thread in a hole or on a boss) with the appropriate cutter.
I can see the advantage to putting EMC on it. The 3M control is very old. The parts will still be available but could (will) be very expensive. One board could cost more than putting EMC on it.
The Enshu mills are very rigid and very accurate. You have some very good hardware there. Some of the best anywhere. That is a jewel of a machine. You will not find anything any better, EVEN new will not be any better. Have I made my point? The mill is very much worth the upgrade to a new control.
Go to www.linuxcnc.org and join the users group. You will find invaluable help there.