Welcome and congratulations, the Old Town canoe with serial number 165389 is an 18 foot long, CS (Common Sense or middle) grade, Guide model with a keel. It was built between July and September, 1956. The original exterior paint color was G. S. (Guide's Special) green. It shipped on April 10th, 1957 to Lincolnton, North Carolina. A scan of this build record is shown 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/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 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.
The most likely candidates would be red western cedar for the planking and spruce for the inside gunwales. More details are available from http://www.wcha.org/catalogs/old-town/specific.gif out of a 1920 catalog and http://www.wcha.org/catalogs/old-town/specifications.jpg from a 1962 catalog. This canoe was made during the transition when grades were being phased out so the outside gunwales may be mahogany. What does it look like?
It looks like outside gunwales may be mahogany. A WCHA classified listing at https://www.woodencanoe.org/classifieds is usually the fastest way to find a good new home for a canoe like this. The messages at http://forums.wcha.org/index.php?threads/57/ may help you learn more about how similar canoes are valued. Good luck with the sale,