The Old Town canoe with serial number 20579 is an 18 foot long, CS grade, Charles River model with Western red cedar planking, closed spruce gunwales, birch decks, birch trim, and a keel. It was built between January and April, 1916. The original exterior paint color was D. G. (Dark Green?). It shipped on April 8th, 1912(?) to Ann Arbor, Michigan. A scanned copy of this build record can be found by following the link behind the attached thumbnail image below.
This scan and several hundred thousand others 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/wcha/ to learn more about the WCHA and http://www.wcha.org/join.php to join.
It is possible that you could have another number or manufacturer if this description don't match your canoe. Feel free to reply here if you have any other questions.