Technical help I.D. these small block chevy valve covers?

I've never seen a pair like these before (but that don't really say much).

just purchased off ebay because I liked the look....

sellers listing said "57 Chevy Chevrolet non script chrome valve covers staggered holes 1955 to 1959, lightly used, good chrome"

look aftermarket to me, hard to tell chrome quality....

any ideas of manufacture?

 

Cal Custom.. They made those and the large finned aluminum ones...

 

thanks for quick reply

 

Depending if not NOS, I figure they are modern "Chi-Com" cheap knock-offs!!

pdq67