I tried on the Nike Watch at the Apple store the other day and you are right about their sales reps. She was not aware the Series 2 was thicker than the S0/S1. She said they did not change the physical size on the S2. I had to lay my S0 Watch down next to the Nike Watch to show her the difference.
She also told me they find out about the new products when they arrive at the store and she did not know if Apple was going to sell the Nike bands separately. I said there is a great website called Macrumors which has the details long before the products hit the Apple stores.
TxWatch