Don't know about a C337, but he used to own an Aerocommander 500S. Rego was ACZ, & I have seen footage of Gina flying it with Lang sitting in the RHS. Later in life ACZ was owned & operated by Augusta Airways, which later became Airlines Of South Australia. I know the aircraft well - it used to do the world's longest mail run from Port Augusta up to Boulia & back. Twenty seven stops within two days. As far as I know it is with GAM now, under a different rego.
DF.