I happened to be in Alexandria today. I logged just one TG, 46. Activity was related to buses. So it seems to me like the new P25 system's TGIDs will be roughly the hex equivalent of the their Smartnet system TGs. They're probably using the buses to test the system and work out the bugs.
I also logged a TG on the Smartnet system that isn't in the database, 1360. I don't know what it is though. I wasn't really paying attention since I figured it was just one of a few newer ones that I didn't already have programmed since it's been a long time since I updated my Alexandria programming files.