The 18" is from the earlier 1960's era. Those "hi-hats" are late 1950's, but I don't believe are hi-hats actually. They are too heavy for that. I think these are band cymbals.
Hi again
I have totally forgotten about checking here for more responses.
Aha, so the Band cymbals then. Are they more unusuall than the hi-hats of that era. And what are they worth? :)