Have a look in the accessories section and you will see a pic of the radio. I expect if it has that written on the front then it is not FE/FC. The FE/FC radio has a black plastic facia with a small badge with the words "Air Chief" written on it. If it was a non-push button FC radio it would also have "Air Chief" written on a plate between the knobs. I think EH or maybe HR radio had "Holden All Transistor" written on it. Someone else may have a better idea of this than me.
I assume you still have the original FC gearbox in it? The EJ motor will go into the FC if this is the case with no problems - You can't use the EJ front engine mount unless you drill out the mounting holes in the front outrigger of the FC. There are other little bits and pieces which are different such as wiring connectors but these are minor and pretty easily sorted out
Ken