Ferd: The canoe would have been made in Old Town, Maine. CS grade stands for "common sense" considered to be the middle of three grades Old Town made. The basic was the "guides special" a functional craft with heavy canvas without any frills as the name would imply. CS was the middle everyday grade, functional for the common man. The highest grade was "AA" trimmed in mahogany as a "high end" canoe. The contrast of woods between the planking/ribs and gunnels, seats, decks and thwarts can be striking.
50# or "light canoe" is the model. OT recognized the need to produce a lighter canoe in 1905. Your canoe (I currently am restoring one) has slightly thinner planking and ribs, the canvas was #10 in an attempt to reduce weight.
If you are interested in more of this history get a copy of "The Old Town Canoe Company, Our First Hundred Years" from Sue Audette and Dave Baker. An excellent book sold in the WCHA store online. - Al