Can a Post machine have more than one accepting state?
According to the description on Wikipedia, there could be more than one accepting state. The truth is, it doesn't matter. The model with a single accepting state and the model with many accepting states are equivalent. A machine of the former kind is also a machine of the latter kind. In the other direction, starting with a machine with many accepting states, single out one of them as the "real" accepting state, and add transitions from the other states to the chosen accepting state.