Based on your decal, your canoe dates roughly between 1967 and 1976. Older but not that old. The earliest Langfords were built from 1945 onward.
Before 1967, the decals on the Langford canoes were rectangular and would have read "Langford Marine on Lake of Bays". In '67 Ken Langford sold the marina but kept the canoe building business and the decal changed to the one you have. Unfortunately, he died in 1968 and the business was taken over over in 1969 in Ken Treadwell. It was sold to a group of corporate owners in 1976 who changed the logo again to a circular design with a beaver.
If there is a serial number, it might be faintly stamped or burned onto on of the stems. Might be hard to see under years of varnish. Typically in this era, they were six digits.
Seems to be in decent shape. You could try contacting the current owners of Langford Canoe Co (who have no connection to the original Langford family) and perhaps they might give you an estimate.