I have owned two of them, a 14'
1948 and a 12' 1949. I still have the '49 and am in the process of completely rebuilding it. The Boles construction is very similar to Airstream -- riveted aluminum upper framework, plywood floor over steel subframe. The aluminum sides are riveted to the steel frame so the floor can be replaced without the need for a "frame-off" restoration. The weakness can come from dissimilar metal corrosion where the steel and aluminum meet.
The last I heard the builder, Don Boles and his wife, are still living and the Boles Aero club holds a get-together every year.
PM me if you would like more information. I am always interested in Boles Aeros.
Sam