Any PCM (or module I'd say) that you buy from a dealer will need to be flashed/programmed thru the Ford IDS or equivalent system. So it's not going to plug-n-play out the box. You don't have a bad idea, it's just going to need a bit more work or other modules such as the TCM to get the tuning that supports all functions.
BTW I did what you are talking about with my old 6.0L PCM and FICM. I had a spare set "just in case" I needed to swap out for some reason.
BTW I did what you are talking about with my old 6.0L PCM and FICM. I had a spare set "just in case" I needed to swap out for some reason.