The Old Town canoe with serial number 176898 is an 18 foot long Otca model with a keel, and the stern seat was moved slightly forward of the usual location. It was built between October and November, 1966. The original exterior paint color was dark green and it shipped on April 13th, 1967 to Houston, Texas. 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. 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.