That Lapp could be used on early 12.5kV / 13.2kV construction as well. There are some who try to collect Lapp insulators by year marking for each style.
I like that black / tan one. Does it have the Ohio Brass monogram on the ear?

Nope. It’s doesn’t have any markings on it at all. I’m wonder myself what company made it.

I see - but the coloring is pretty consistent with earlier Ohio Brass production (1910s and earlier tended to be a reddish brown, then late 1910s-late 1930s OB insulators were mottled black / tan like that one, and then in the early 1940s they went to a uniform chocolate brown).

Nice collection there!