Before it was a Berkeley kit it was published by Chuck Hollinger in the Jan 1955 edition of American Modeler magazine.

By the way, the Berkeley kit called for a .15 to .19, and the engines available at the time in those sizes generally produced way less power than equivalent sizes do now.

No doubt Sig has modified the structure some, but I bet you could still fly one on a modern .15 if you kept it light.

Have fun with your piece of modeling history!

Jim