Here is a Dueco Artist Model with a Vintage Burst style finish on a 12-Fret body with rolled F-holes. This would be the same body style that National used for a short time in 1934. It was just before the 12-fret body was replaced by the 14-fret body. The rolled F-holes are shorter, but the bend in the steel that the stamping die makes stiffens the top. Standard 12-fret Dueco Models have flat cut F-holes.