The Old Town canoe with serial number 78707 is an 18 foot long, AA (or top) grade, Ideal model with red Western cedar planking, open mahogany gunwales, mahogany decks, mahogany thwarts, mahogany seats, half ribs, a keel, outside stems, and a bang plate along the full length of the keel. It was built between May and July, 1923. The original exterior paint was dark green. It shipped on July 25th, 1923 to Peekskill, New York. This clearly isn't a 16 foot long canoe so you may want to verify the serial number again.
The Old Town canoe with serial number 174796 is a 16 foot long Otca model with narrow two and 3/4 inch planking, a keel, sponsons, and the stern seat moved two inches forward of the usual location. It was built between April and August, 1965. The original exterior paint color was dark green. It shipped on October 21st, 1966 to Utica, New York.
Scans showing both of these build records can be found below. These scans and several hundred thousand others 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
http://www.wcha.org/about-wcha to learn more about the WCHA and
http://www.wcha.org/store/membership to donate or renew.
It is also possible that you could have another number or manufacturer if these descriptions don't match the canoes. Feel free to reply here if you have any other questions.
Benson