Yes, years need to be taken into account just to make sure you do get an Aerostar with an A4LD, that would be 1990-1995. If it's got both the 4.0L OHV and the A4LD, I'd expect both to drop into the Explorer together or individually.
Just double-check that the bellhousing is the same on the Aerostar before you try removing the trans. You'll be uttering some choice words, I've seen the 4.0L in an Aerostar and I wouldn't even want to change spark plugs in one.