Picked up a popover pan today, only markings I can see are Made in USA, physical appearance is the same as the Wagner Ware Number 10 and the Griswold Number 10, Here are some pics, I'm thinking Wagner Ware post 1959.
It is in the lye tank right now but before it went in I took a good look at it, very well made, nice smooth finish.
Ironically when I picked this one up there was an identical popover pan underneath it, Except it was marked made in Taiwan, They both appeared to be the exact same sizes and finish.