I think I can help you with this. I had a 1980s' silk dress many years ago with that label, and although I no longer have the information that I found at the time, I was able to ascertain with a fair amount of certainty that this was indeed a very early line by "the" Carmen Marc Valvo. It may have been done specifically for a particular department store chain or chains, but it pre-dated his Carmen Marc Valvo labels. The dress I had was really lovely--very high-quality silk, nicely made, and classically stylish.
Oddly enough, I had a Carmen Marc Valvo dress a couple of years ago, made while his name was big, and it wasn't as nicely fashioned as the other, earlier piece, made before he was famous.