Personally, no, but that's due to a lot of other factors, such as style, age, prospective salary, lack of playing time in the Premiership etc.
But I do think for the right club he's probably worth that, yes. Based on age, Championship record, previous market value etc.
Anyone that pays £12m for McCormack this January needs a lesson in how to negotiate. The guy's value has dropped markedly, and anything over £3-4m would seem over the top.