As I understand it, the compass selector on the autopilot is supposed to provide a heading hold function. In other words, it is supposed to function like the heading bug on a modern autopilot, with heading hold being the only function the old autopilot provides. On my DC-3 v1.4 the compass selector turns the card but it seems to do nothing as far as holding the selected heading.
Also, the artificial horizon on the autopilot doesn't follow the other ones.