A quick check in the service manual shows that the answer is yes – you will indeed get both line level output (Playback Left and Right) and line level input (Recording Left and Right).
The AUX on the BC2500/2300 also has both Datalink pins connected, but to different Datalink protocols. Pin 7 has the "old" 8-bit pulse train codes for control of a second tape deck (TP2) or turntable (PH), while pin 6 is used for the Audio Aux Link to a video system. This means that communication on pin 6 is in the "new" Datalink 86 protocol.