A few things,
a) P&W logo on #2 engine.
b) The only other similiar looking engine for that model was the CF6-50.
It doesn't have the pointed tail cone like the -50. Have a look at some
KLM 742's and you'll see what I mean.
c) Commercial Jet Aircraft Census - http://www.bird.ch/bharms/asr_sh00.htm
lists the original build config of this particular Air Madagascar A/C with