...it's been my experience with this and several other chips that just about all of them were cancelled and just about all of the cancelled chips have had their cancellations removed.

Has anyone seen, for example, a Castaways $25 N4071 with the cancellation intact? How about an Oliver's New Castaways $5 N3733? Or a Don French's Bonanza $5 N2323/N2322? I've never seen any of these either uncancelled or with the cancellation foil intact.

My assumption, in this case, would therefore be that the seller had nothing at all to do with the removal of the cancellation mark... virtually every sample of this chip has been cancelled and then "un-cancelled".