It's a bit of an oddity because it doesn't follow the divide/multiply by 16 "rule." I think that's because it's a holdover from the old analog MassPort trunk. As I recall, MassPort changed the TG for the P25 F-Patrol-1.
Bill, do you hear both 33392 and 1072 on Zone 1? I seem to remember hearing both on Zone 1, but only 1072 on Zone 5. I'm not in town all that much anymore, so I don't know what the current situation is.
To make it even more confusing, I seem to remember hearing TG67 on the Boston 700Mhz Overlay campus as well. I think I'll plug that into my SDR set up and see what pops up over the next couple of days.