This 1956 BSA DBD34 has matching numbers. It was exported to Hap Alzina the USA West Coast distributor.
It was re-imported back to England in the late 1980's. Chuck Minert won the 1956 Catalina GP on a DBD34 Scrambler and in 1959 BSA created the "Catalina" in tribute to his win. This model is the 'Scrambler' as depicted by the silver fuel tank as opposed to the blue tank which the "Catalina" had.