Its too bad you didn't do a little research. If you chose the PRR G4 Class #7124 the Belpaire Boiler is not as pronounced
Unlike the PRR G5 #5741
Which is at the RR museum of PA that has a prominent Belpaire Boiler as well as the Air tank on the front. Maybe METCA can make some number changes.
BTW I am not aware of any O gauge/O scale PRR G4 class locomotive made.