Jon-
Yes, there were stamped Campagnolo dropouts, we referred to them as the Gran Sport version. Came with threaded eyelets. The vertical drops were the made the same way, both were thinner than the classic forged units.
Bertin used the horizontal ones on the C-35 in the mid 70's. I am sure some others beyond what you and I have seen did as well.
John Jorgensen
Palos Verdes Ca USA