The Old Town canoe with serial number 157433 is an 18 foot long, CS (common sense or middle) grade, Otca model with a keel. It was built between March and May, 1952. The original exterior paint color was dark green. It shipped on May 20th, 1952 to Gwinn, Michigan. 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 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 possible that you could have another number or manufacturer if this description doesn't match your canoe. The messages at http://forums.wcha.org/showthread.php?57 may help if you want to value or sell it. The classifieds here at http://wcha.org/pp-classifieds/ are often the fastest way to find a good new home for a canoe like this. Feel free to reply here if you have any other questions,