Dan, mcguffeyd1, and I have been back and forth on these signs a couple times. I explained to him this is a sign I would ONLY buy from a reputable dealer in the hobby as there are just too many perfect ones on Ebay, frequently from the same sellers. It has scared me from buying one for sure and I do not own one of these signs for this reason. The only ones I know are good are normally too toasty for me to be interested in.
I had questioned the authenticity of these signs probably 3 years ago on Old Gas and I don't think a conclusion was ever reached. At that time they were possibly new to the market, but now I see them so frequently I personally do not think that 99% currently available on-line are genuine. When Scott listed his I wondered about it, but I question almost every one I see. I will say however that the Mobilgas Special version is quite a bit more scarce and I have not questioned any of that version, YET! I'm sure it's only a matter of time before they show up frequently in perfect condition as well.
I think something to keep in mind is this is a tin sign. We all know unless there was a "warehouse find" of perfect signs the probability of a large quantity of them being NOS is slim. Generally warehouse finds in this hobby are hard to keep secret, so if one was found I think someone would know about it. That's what doesn't sit well with me here, especially with the age of the original sign. The first dated porcelain shield pump plates are marked IR46. IF most of these tin signs were used for approximately 5 years they should show some signs of use, but almost all appearing these days are NOS. Again....something just doesn't add up.