Yes, as long as the passes are linked to your MDE account. Linking may have happened automatically when you purchased, but if not, you should be able to do it manually. (Call MS if you have trouble doing that - either they will assist or transfer you to someone who can).
I purchased a DVC annual pass several months prior to our recent trip (just got back 12/6/17) and had no trouble at all making our FP+ reservations at the 60 day mark.