Motor Question(cross posted)

I've got a flame cutting machine with an optical tracer which I'd like
to convert to CNC control. It has small DC gearmotors which drive
both axes now via the output from the optical tracer. Here's the
complete data from the motor nameplate. The machine was built in 1983.

Pittman
MT9414C369
3501D74H01 Rev A
19.1 VDC

Pittman's website shows a GM9414 gearmotor which has roughly the same
physical dimensions. Here's where I'm stumped though:

There are 4 wires to each motor, all running in a common vinyl
jacketed cable. Two wires go into the motor at the shaft end, and the
other 2 go into some smaller "device" which is attached to the
opposite end. I'm assuming these devices aren't encoders, since all 4
wires are running together? Pittman's site mentions the availability
of pulse generators outputting something like 120 counts per rev, but
there's no picture I can use to see if this is what they may be. A
burning machine is a slow and relatively low accuracy machine, so I'm
sure these aren't rocket science caliber drives, but I'd like to know
whether anyone has any idea whether I can use them for a conversion or
if I need to just forget them and adapt something else. I haven't
actually checked to see if the device attached to the motor is
removable or not. Guess I should do that to determine if proper
encoders might be mounted in their place? Any ideas?

TIA
Cliff