Yes, it's a common mistake. That's what happens when a builder makes two completely different models of the same length, even if not at the same time. Perpetual mistaken identity.
Yes, the rudder is skeg hung, with the propeller in an aperture -- not the best for backing down, but well protected from pot warps (we pay them little heed and often sail right over them).
Sounds like you got a great deal on a solid boat, even if it needed some work. Enjoy the breeze!