Well, the handy dandy .pdf chart I was given by a forum member says it's a:
Model 66K, Allotted #: 60,000, Allotted date: Jan 12-1923.
The K means it was made in the Kilbowie factory, Clydebank, Scotland.
Is it electric, or treadle?
It uses standard 15x1 needles, Class 66 bobbins, both can be had most anywhere.
External parts can be had depending on what your needing. Belts are easy to come by weather electric or treadle.
Congrats on the machine. I have 5 66s. I kinda like 'em.
Joe