In your first picture, that's a very unusual reed switch 'n magnet wheel modification.
Never seen anything like it.
Looking at the white disc part, it appears to be made specifically for the mount.
And if that's a 24 magnet disc I see there, that would be a step up from the usual 10 pulses the AJAK gets (which isn't bad).
The original had five large magnets on a disc, and the reed switch was rigged to get two pulses per magnet.
Very clever design, but probably not easily upgradable to more pulses (with the reeds of the day).
Today, we have tiny reeds, and ultra small magnets, and -could- make a disc like the original.
Yours appears to use a multi-pole magnetic disc, and the only question is: how many poles does it have?
8, 12, 24, would be common today.