I went to the store to pick up some SD Adult Original dry for my cat. There
was none on the shelf and when I asked the salesclerk about it, she pointed
out the bag of SD Oral Care Adult. She told me that Adult Original was now
Oral Care Adult. I had my doubts, but bought the Oral Care, anyway. I have
since checked Hill's website and find no information to back up her claim.
Could you tell me if the salesclerk was correct, or if perhaps she was just
misguided?

She was mistaken. You'll notice when you open the bag of Oral Care that the
kibble size is much larger, for example. The nutrient levels are pretty much
the same so there is no problem there.