Other than the service dial, which is still both highly collectible & valuable, I do not see the fly in Bikoff's ointment? Further, Dowling, who I know to be an honest, knowledgeable & reliable collector, was 100% accurate in his description of the 6538 in question - ' The dial is an original factory replacement one, as supplied by Rolex from the mid 1970s, it is identical to the original one except that it is a matt finish, not gloss and all the text is in silver, as distinct from the gilt/silver mix of the original. But, like the original, it has the outer minute circle and the 200m = 660ft marking.' It sounds like Bikoff was either less than honest in HIS sales description or he received some very bad guidance along the way.
As for Dowling being an RWG member, I highly doubt it. But I believe he has perused our pages on multiple occasions.