They are not gibsons but modelled after the Gibson F5 that were started being built in the 1920s (Those instruments run 6 figures today that were built in the early 20s). Bill Monroe made the Gibson models famous. Many builders build models based of off that F5 body style. The Luthiers for my two are John Monteloene and Lynn Dudenbastol. On the headstock calls out their last names. Both are part of the elite Luthiers building instruments today.