The Old Town canoe with serial number 176545 is a 16 foot long Guide model with a keel. This originally had thwarts in place of seats and then seats were added later. It was built between July, 1966 and May, 1967. The original exterior paint color was G. S. (Guide's Special) green. It shipped on May 29th, 1967 to Burlington, Vermont. 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/join to donate or renew.
It is also possible that this canoe could have another number or manufacturer if the description doesn't match. Feel free to reply here if you have any other questions.