The Old Town with serial number 178338 is a 15 foot long light weight model with a keel. It was built between May and June, 1967. The original exterior paint color was brown. It was shipped on July 25th, 1967 to Chaplin, Connecticut. A scan of this build record can be found below.
This scan and several hundred thousand more 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/catalogs/old-town/records/ if you want more details. I hope that you will donate, join or renew your membership to the WCHA so that services like this can continue. See https://www.woodencanoe.org/about to learn more about the WCHA and https://www.woodencanoe.org/shop to donate or renew.
It is also possible that you could have another number or manufacturer if this description doesn't match the canoe. The sail rig is not mentioned so that may have been added after it left the factory. Feel free to reply here if you have any other questions.