Have done a little sleuthing. On the assumption the a/c was a deH product registered in Uruguay, the most likely candidate would be CX-API. This was registered in Uruguay in 1954, remaining on the register until as late as 1972 (wonder what happened to it then?). Registered owners mentioned; Delfin Dias Giblis Montevideo then to F Deismann (or Oetzmann) Montevideo. The other deH twins were off the register by 1954.
Other possibilities would be a DC3 or a Beech 18, both tail draggers and not unknown in that part of the world.
A photo of CX-API appears in John Hamlin's book The de Havilland Dragon/Rapide Family.