You have maybe noteced alikeness of caps from different factories or even cities. Indeed, fonts were changing during production years. I mostly like old 50th, 60th! Standard fonts described in GOSTs. So, I googled and discovered some: GOST 2930-62, GOST 2.304-81, GOST 26.008-85.
Knowing GOST, we can more precisly production period of caps. Not bad! We will be able to compare caps from different factories.
I have idea impliment tags in our site to mark with them catalog items in particular. Tags may describe fonts as well. Having this data, we can show the catalog in other views.
If you know other GOSTs, let me know. Information will be reflected in the catalog!