Not only are parts still available, the Model K is still in production, with a list price of USD $2100 without the motor--which, btw, is actually an add-on that only replaces the pump HANDLE. It's the only toilet still made in the US that's even close to the British Baby Blake. Hopefully you still have the pump handles for both toilets 'cuz you'll need them after you remove the motor.
If you didn't get any documentation with them, these links may be useful to you: