On my fx3, the rear derailier, is acera, but on the website , it says it is supposed to be alivio.
I chatted with one of the trek people on the website, they say it is interchangable and it depends on what is available at the time.
I bought this directly from a trek store, and i'm just curious is this normal?

shouldn't it be alivio, since i thought alivio is step higher