I know the original post is an older one, but, just to clarify things. Occupational therapists are often trained in hand therapy and the therapy of the upper extremity as a whole. So, it is not uncommon for patients who have had any type of upper extremity surgery to be referred to an OT.
OTs also deal with the rehabilitation of stroke and burn patients, but that is not their only emphasis.
So, shoulder patients could be referred to either an OT or a PT. It is possible that the surgeon and that OT had worked together, and the OT knew exactly what the surgeon wanted for his/her post-op protocol.