As far as I can see, we may have the build record for your canoe! I was suspicious that it may not be an Old Town, as 4-digit serial numbers on OTs don't come up often.
Old Town 6668 is a 16 foot AA (top) grade Charles River model canoe which was finished between April 1907 and February 1908. It has red Western cedar planking and mahogany decks, thwarts, seat frames, and double gunwales. The double gunwales are a telling-feature of this canoe and your canoe appears to have them... plus your canoe appears to have the lines of the Charles River model... so this may be the correct record. The canoe was shipped to Cincinnati, OH, on March 4, 1908. If you are in the vicinity of Cincinnati, that might be the clincher.
I'll post a picture of the double gunwale, for everyone's information.
The scan of this record is attached below-- click on it to get a larger image. This scan and several hundred thousand others were created with substantial grants from the Wooden Canoe Heritage Association (WCHA) and others. A description of the project to preserve these records is available at
http://www.wcha.org/ot_records/ if you want more details. I hope that you and anyone else reading this will join or renew membership in the WCHA so that services like this can continue. See
http://www.wcha.org/wcha/ to learn more about the WCHA and
http://www.wcha.org/join.php to renew.
Kathy