Wound vs PM DC Motors

Upon close examination a couple of my recent DC servo motor
acquisitions (for X and Y) appear to be wound field motors and not
permanent magnet as claimed by the seller. Inside they look like the
generator on my old MG, with field coils wrapped around a shoe. I
foresee a potential problem because my servo amps specify permanent
magnet (brush) DC motors.

My thinking was that the motor can't tell if its stator is a
permanent or an electro-magnet. But apparently it's not that simple
when the field coils are not independently energized. The makers
plate on the motors says "SPLIT SER". My Golden Book of Motors
discusses the basics of series wiring of field coils, but doesn't
discuss split series.

Apparently wound DC motors can, depending on configuration, require
additional amplifier functionality to switch the field coil polarity
for reversing, etc. My amps don't appear to be equipped to do this.

Would it be possible to re-wire the field coils so that they are
independently engergized at a constant, unswitched level so as to end
up with a virtual PMDC motor with nameplate torque and speed
characteristics?

Thanks in advance.

--Jack