Welcome and congratulations, the Old Town canoe with serial number 174869 is a 16 foot long Guide model with narrow two and 3/4 inch planking, a keel, and the stern seat was moved two inches forward of the usual location. It was built between May and June, 1965. The original exterior paint color was dark green. It shipped on June 15th, 1965 to Alexandria, Minnesota. 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. 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. Canoes with a family connection are always extra special. Let me know if you have other questions or if there is anything else that I can do to help.