just a wild eyed guess...could this be 44-13257?
This is a picture of Roberto Ibarguen, taken while he was undergoing Mustang training in Florida. The same picture appears on the Latin American Aviation Historical Society (LAAHS) website. The article is called "TG-REI : a Guatemalan Mustang". There is also a nice piece about Dominican Mustangs by Luis Puesan, with many Mustang profiles. The plane: my best guess is 44-13257, at that time N4222A, Cavalier F-51D MkII demonstrator, now N51DL, still wearing camo colours (I hope...). The 6 Salvadoran F-51D MkII, which might have been at the Cavalier plant at the time the picture was taken, had the same camo pattern, but, from the pictures I've seen, the Tan area on the cowlings didn't reach that far down, while it did on N4222A.
Martin (Swiss Mustangs)
Hi pals it IS N4222A - the Cavalier Mk. II demonstrator! Camouflage pattern matches perfectly when comparing with other pics I have (from its 'active' demonstrator days) - today the camo pattern is different. Greetings Martin (Swiss Mustangs)