its not that easy as Qantas also has 3 secondhand GE
-powered 744s in its fleet since 1998.
I´m a 747 fan and I can´t tell a 744ER apart from a normal 744 from the outside. That is also the case with 744Fs/744ERFs. They look the same.
The only difference aside the engine issue on QF
aircraft is that the ERs miss the front underbelly antenna. But that is the case with all 744s built since a year or so.