The Old Town canoe with serial number 177276 is a 17 foot long Otca model with a keel and a stern seat which was mounted at 32 inches. This is slightly forward of the usual location. It was built between December, 1966 and May, 1967. The original exterior paint color was red. It shipped on May 23rd, 1967 to Southwick, Mass. A scan of this build record can be found by following the link at the attached thumbnail image below.
This scan and several hundred thousand others were created with substantial grants from the Wooden Canoe Heritage Association (WCHA) and others as you probably know well. 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 will join or renew your membership to the WCHA so that services like this can continue. See http://www.wcha.org/about-the-wcha/ to learn more about the WCHA and http://store.wcha.org/WCHA-New-Membership.html to join.
It is also possible that you could have another number or manufacturer if this description doesn't match your canoe. Feel free to reply here if you have any other questions.
I don't know the exact reasons but the build records from this period often have notes about moving the stern seat forward slightly. It may have been compensation for heavier paddlers or simply an attempt to make the canoe slightly more stable for people who insisted on paddling a canoe alone from the stern seat. Consumer Reports published a review of canoes in the late 1960s or early 1970s where one of their tests included a subjective measure of a canoe's stability when paddled alone from the stern seat. It would have been more funny if some people weren't actually making purchase decisions based on absurd tests like this.