It has enough similarities (both species are wizards, both have a small fixed number, both created through a ritual gone wrong, both are evil), combined with the illustration, to at least give grounds for a law suit, if not guarantee a win.
As for them being around since 1983, I've been playing since 81, on and off, and haven't come across them before (maybe they looked less skeksislike?), and as far as I know the Raven Queen was a 4e addition.
The originals are fixed in number, but they might be capable of reproduction.