Problem is that its in the gray zone. Its higher that 355300 which was the top end in 1906. After that, the records are lost and its a guess. What you got on the other site were probably other peoples estimations using slightly different assumptions. The guy telling you it didn't exist was likely looking at Col. Brophy's book on Marlins, the definitive text on the subject. Brophy notes that the highest "observed" SN for a Model 92 is 436,495. Yours being above that range is new data, at least at the time of the publishing of Brophy's book. The model ceased production in 1915, so yours was clearly built between 1906 and 1915, most likely in the last year. There is some probability that it was slightly later, if Marlin like other mfgrs of the time, continued to build guns with parts on hand after catalogued production ended. This maybe more of the frustrating uncertainty you have already encountered, but there may not be a verifiable answer.
