Welcome and congratulations, it appears that you have a 16 foot canoe but the Old Town and Kennebec records for number 8458 both show 17 foot canoes. The Carleton record for this number shows 16 foot canoe so some pictures for your canoe including the areas around the serial numbers from both ends would help. The tricks at
http://www.wcha.org/forums/index.php?threads/791/ may also be useful.
The Carleton canoe with serial number 8458 is a 16 foot long, CS (Common Sense or middle) grade, Carleton model with western red cedar planking, closed spruce gunwales, ash decks, ash thwarts, ash seats, a keel, and sponsons. It was built between July, 1911 and May, 1914. The original exterior paint color was dark red. It shipped on May 9th, 1914 to the Greenhut, Siegel, Cooper Company in New York City. (Macy's sold the Old Town line at this time so other dealers in the area sold the Carleton line.) Scans of both build records can be found by following the links under the thumbnail images attached below.
These scans 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 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 join.
It is also possible that you could have another number or manufacturer if this description doesn't match your canoe. Feel free to reply here if you have any other questions. Let us know what you find,
Benson