No stampings, they were paper labeled I believe. Yours maybe are both pass side? Drivers side I dont think ever had tabs or looms. Tabs and looms on pass side changed whether 2 or 4bl as well as year changes.
Oh, wait, maybe not, I just read thru this thread again and see that other wire loom guide in the center of one of the valve covers, mine don't have that piece.
I guess none of these valve covers have any part numbers stamped on 'em either.