The Old Town canoe with serial number 181143 is a 16 foot long FG (fiberglass) model with a keel which weighed 85 pounds when it was built in July of 1968. The original exterior colors were white decks with a blue hull. It shipped on July 25th, 1968 to Bethlehem, Penna. The back side of the record indicates that there was no hardener in the microbaloons in the keel. Scans showing both sides of this build record can be found by following the links at the attached thumbnail images below.
These scans and several hundred thousand more 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.