Nick, Very interesting. In your numbers, the receiver #6333E circa 1911 Grade 00 (Field Grade after 1913) Barrels #6065 circa 1910 Grade 2 (after 1913 Specialty Grade) and forend 216697E circa 1913 (10 ga, 12 ga 16 ga.) Does the forend have a banjo shaped escutcheon with a roller release on it? The "E" in the serial number is for ejector guns, and do the barrels have the split extractor rod/s? If you can post some pictures of it I'm sure someone can give you a ballpark value if you are interested in selling it elsewhere.