I haven't played a lot of 1-3-1 zone (in BB) but I think that most corner three point attempts are contested by players on the wing of the zone, not guy at the bottom in the game engine. If this is in fact the case then I find it pretty unlikely that the simulator would run the PG on the bottom of the zone.
I think that it currently runs as:
..............................
.............PG..............
..............................
SG..........PF............SF
..............................
.............C..............
...........basket...........
Another related question:
I can't figure out who is playing where on a 3-2 zone. I know that the PG-SG-SF are on the outside (obviously) but I can't figure out who is playing in the middle and who is on the wings. Presumably it'd be the PG in the middle, but simulations don't seem to give a clear indication of whether or not that is in fact what's happening.