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I was looking at the same model. It is a legit EG Westminster shoe, probably custom made, you can order any edward green shoes with any color combination you wish. This is not uncommon. However word of warning if are planning on buying this shoe ask seller to send you a picture of the box with description of the product. I am not sure if seller understand EG sizing. The seller has indicated this is wide width shoe, usually in US size E is wide. However EG E width is medium width which translates into American D width see how confusing this gets. So the best bet is to ask seller for the picture of the box where it is written what shoe it is, color of the shoe, sizing and last information.
You're right, it could be a custom order. However, I was hoping it was an old model since my size is sold out on ebay, so I was hoping to find another pair somewhere else. Of course I could go MTO but for now that's a bit out of my price range, being a passionate C&J customer. I've also considered ordering a MTO from Ed Et Al, but of course that would not give me a pair of EGs, just a pair of nice double monks (presumably).