If the listed pipe was bought by the seller "many years ago" as he claims, that would likely put it before the Internet/Ebay era, when pipes fetched nothing like they do today (an estate Dunhill billiard could be bought all day for less than $100 thirty years ago). Which throws still another false note into the proceedings. Namely, it would have had to have been counterfeited BEFORE counterfeiting pipes was an economically viable thing for crooks to do.
Which argues either for originality, or the seller is spinnin' a yarn.
If forced to bet at this moment, based only on the photos and this thread's comments, I'd guess it's a factory pipe by that was "retro-fitted" to look like a Dunhill.
Another point I realized since my previous comment is that Dunhill's wood orders/processes almost never resulted in straight grain orientation, and when it did, the pipe was always given a DR stamp. They were worth considerably more in the market, and making money is any company's reason for existence. That one would not have been overlooked.