Joe,
Gamba Brothers was an old established gunmaking business that dated back to the 1940s. The brothers disolved the business in the late 1960s or maybe early 1970s, and machinery was sold to Renato Gamba, who I believe is a nephew. Gamba Brothers was very well respected in Italy, and they made some very nice high-end shotguns, as well as others less expensive. Gamba Brothers (or Renato Gamba) made the Mauser 580 side-by-side that was imported to the US in the 1970s, which is a nice, mid-range side-by-side representative of Gamba's overall quality.