I think Linuxman has that dish on an Ajak.
Though whether it came that way or he mated 'em in the field, I don't know.
From what I've observed, the AJAK motors were adapted to each dish brand.
Some were more custom-adapted than others.
(anyone with more info, please jump in. edit: thanks Pendragon, I see you beat me, too.)
It's pretty obvious from your pictures, how the declination works.
You just haven't shown all the pieces.
As for how many degrees per hole, you could easily check that with an inclinometer.
I wouldn't be surprised if it's the 0.5° per hole, but is limited to a restricted range (not starting at zero)
Something like 4.5° to 6.5° would pretty much cover most of the contiguous United States.
That would be: 4.5°, 5°, 5.5°, 6°, 6.5°. - or five holes (which is just a guess)
If one degree steps, then...3.5° to 6.5 would go below Texas, and slightly into Canada.
So maybe: 3°, 4°, 5°, 6°, 7° - for the five steps (I might gamble on these numbers)
Birdview dishes had a fixed 5° (?) degrees of declination built into the mount at the factory.
If that wasn't good enough for you at your location, your installer shimmed it with some washers to bring it up or down a little.