Yes, a few different autopilots exist, but there was not enough time during development to do a manual for the Arrow (recall, Arrow was an afterthought for Dan). When Dan has more time and actually gets paid and does some pay-for work, he will usually gives many hours of that time to the Orbiter Community. So, I would anticipate that the Arrow mk.II will have some different ship areas, different autopilots, and advanced features that will make a manual necessary.
Cheers,