I would say if it's been fitted with servos and a CNC controller from new, it's got to be a good candidate. Could be worn out of course but a lot of the work will have been done for you even then. If you spot one of these with an old controller, it may be a good price and not hard to update. The X and Y servos (and belt drive covers) are easy to spot. If it's only 2 axis, you can do the Z axis yourself.