The Old Town canoe with serial number 75630 is an 18 foot long, CS (Common Sense or middle) grade, Otca model with open spruce gunwales, twenty inch birch decks, birch thwarts, and birch seats. It was built between December, 1922 and June, 1923. The original exterior paint color was gray. It was shipped on June 8th, 1923 to Philadelphia, Penna. If you really have a 16 foot long canoe then my guess is that it may be the one with serial number 175630. This is a guide model with a keel. It was built between January, 1965 and May, 1966. The original exterior paint color was G. S. (Guide's Special) green. It was shipped on June 15th, 1966 to South Weymouth, Mass. Scans showing both of these build records can be found by following the links at the attached thumbnail images below.
These scans 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 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 renew.
It is also possible that you could have another number or manufacturer if neither of these descriptions don't match. I would encourage you to measure the extreme overall length of your canoe in a straight line and attach some pictures of the serial numbers from each end here. Feel free to reply if you have any other questions.
Benson