Hi--
Was the keel removed and placed inside the canoe, or is that a keelson? Except for the war canoes, Old Towns don't have a keelson. Your decks have an Old Townish ogee shape, but thwarts are different and outwales don't look quite Old Town to me-- Old Town open gunwales have a "huskier" look (just my impression-- those of you who have actually reproduced them could answer this with greater authority).
Old Town serial numbers appear on both stems. Some of the other canoe companies put the numbers on the stem too, but often only the bow or the stern. Getting only the last three numbers doesn't help much, when it comes to Old Town... there'd be thousands and thousands of numbers to pick through... and the task would be similar to spinning straw into gold.
Over the years, there have been lots of good suggestions offered here in Forums for visualizing the digits in serial numbers. Here are a few that come to my mind:
(Remember to compare numbers on BOTH stems)
Carefully scrape off surface paint/varnish, or use paint stripper to reveal numbers
Wet the area
Do a rubbing: Place paper over numbers and go over the paper with chalk, crayon, pencil or whatever
Take a picture with a digital camera and post the picture in Forums
Here are a couple of thrilling videos which show the process of finding the serial number and looking up the build record:
http://www.youtube.com/watch?v=LYwVSJhejFA
http://www.youtube.com/watch?v=plUn6oHDHyQ
Good luck finding more digits--- others should chime-in with their thoughts about your interesting canoe.
Kathy