Jeff's serial number list has it built in 1902. My experience with this very involved serial number list is that it is extremely accurate. You say it's a sideplated boxlock? If it's a hammer gun of the typical Sauer pattern of the period, it's more likely a sidelock, not a boxlock. I have at least three like it, one actually finished and marked by Max Fischer, Berlin, which is one of my favorite 16 gauge guns for upland hunting.