Now, the question is: all references I found indicated it was a component of LABS; how deeply was the indicator integrated into the bombing system?
Only to the extent that a current Flight Director is integrated into the Attitude Indicator...
The AJB-3 had a set of needles that cued pitch and roll/heading for LABS. Other than that, it was used as the normal attitude indicator when the weapons system was disarmed. The advantage was that it did not "tumble" like a normal attitude indicator when going through the vertical -- it was stable through any maneuver.