Considering how many SE-5s, Nieuports, and even a few German aircraft were imported after the war, finding a wing-spar made out of wood from Europe might not be so rare.
There are so many stories about finding wreckage of "The White Bird" that they span from the coast of France to the woods of Maine.
"Major modifications included the reinforcement of the plywood fuselage, removing two of the forward cockpits with the main cockpit widened to allow Nungesser and Coli to sit side-by-side. The wingspan was also increased to approximately 15 m (49 ft). In adding two additional fuel tanks mounted aft of the firewall, the three fuel tanks held a total of 4,025 litres (1,056 gallons) of gasoline."
The PL.8 was modified from the Levasseur PL.4 French recon plane. A couple of things to note about this was that the PL.8 aircraft was never tested with a full load of gasoline, and that the PL.7 (also modified from the PL.4) was grounded in 1931 after two disintegrated in flight, which was attributed to vibration.