yup, I bought from gerrutcamaro before too. Actually, I can recognise a lot of the IDs of the people buying this set as matching sellers' IDs on eBay. I think rule of thumb is that if its a loose Headmaster head, there is a good chance that its not the real thing.
Like Kup said, I don't think these repros will actually devalue the actual heads, the problem with the actual heads are that no one can actually find any!