I immediately took advantage of my new membership in the Cloudy Nights forums. I asked if anyone had the Vixen Super Polaris mount with an intact Declination plate. And, if so, if they would be so kind as to photograph it (in macro mode) for me.
Tim (tim53) came to the rescue.
Now I can finally add the missing Japanese to my vernier scale!
Interestingly, Tim is undertaking a project to GOTO-ise his Super Polaris!