The person I obtained it from had said it was a Chestnut (missing the decal) but after posting on the WCHA forums, some better experts chimed in. Many features, like the decks and narrow red cedar planking meant it wasn't a Chestnut at all, but rather resembled a late model Richardson /Rilco, the successor to the bankrupt, Lakefield Canoe Company.
However, there were some inconsistencies with original Richardson / Rilco builds - most notably that these canoes had narrow, tapered red cedar planking that ran all the way from bow to stern, with no goring pattern. Mine however had a distinct goring pattern with shorter pieces of planking along the bilge.
After reading a forum post by another person (Grizzle) searching out a Langford Canoe decal, it become apparent that our canoes shared many features. To my eyes the overall lines of the canoe look very much like Grizzle's confirmed Langford.
Mine before repainting
Andre Cloutier's Ravenwood Canoe blog has been most helpful in confirming this as well. This post from 2012 discusses a Langford restoration along with some interesting history of the company. The photo closeup and detailed description of the decks demonstrated our decks were identical too....
Confirmed Langford Deck
Photo Credit: Andre Cloutier - Ravenwood Canoe
The seats on Richardson/Rilco boats are also mounted on bars below the gunnels. However, it seams that Langford hung the seats with fine steel bolts with countersunk and plugged holes, whereas Richardon simply left the bolt heads exposed. Also I've noticed that Richardson/Rilco canoes alternated lacing holes on all 4 sides of the seat like so...
Richardson / Riclo weave pattern
...while the few Langford canoes I've stumbled across have straight lined holes on 2 sides like this:
Langford Weave Pattern
Original Link: A Cloutier - Ravenwood Canoe
Grizzle's Langford Seat
While the lacing has disappeared on my canoe and the seats covered in a plywood plank, I took the time this summer at the cottage to inspect the lacing hole pattern still visible on the underside of the seat (sorry no pics). As an additional confirmation to end the mystery, the pattern matched the Langford lacing method.
A subsequent post on the WCHA forums linked to a Flickr page of Steven DeFehr who posted a web album featuring a 17' Langford Canoe from 1979. Included in his set is a document listing the various models and stats.
1979 Langford Canoe Models & Pricelist
Photo Credit: Steven DeFehr
How the beam is measured can vary from builder to builder so the beam measurement on my canoe is a bit off. But the length, depth, rib width and approximate weight seem to line up - so it seems my mystery canoe may be a 15' Trapper model.
Despite the obvious build quality issues on my canoe I've been happy using it as my casual lake and river poling canoe. It'll be my beater boat until its time is done.