According to this footnote at aerospotter.blogspot.com, at the end of a larger article on Argentine C-46s, it was Bolivian-registered C-46A 41-12290/CP-746:
Roll Out wrote:
La aeronave en cuestión era el Curtiss C-46A-5-CU registrado como CP-746, cn. 26417. operado en ese momento por la compañía Servicios Aéreos Oriente.
Full page here:
http://aerospotter.blogspot.com/2011/01 ... ntina.html
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All right, Mister Dorfmann, start pullin'!
Pilot: "Flap switch works hard in down position."
Mechanic: "Flap switch checked OK. Pilot needs more P.T." - Flight report, TB-17G 42-102875 (Hobbs AAF)