The doors with the one piece glass are 74 only (for the 140), and will directly interchange with 240 up to 79 at least. Later ones will work too but the latches are different. So are the molding strips.

If you really want to get tricky I've seen a couple of cars with late doors that have had the early (71 and back) protruding door handles adapted.

Hanging the doors can be either very easy or very tough. Unfortunately there is no way to tell in advance. Sometimes they go right on and fit perfectly, sometimes they require hours of fiddling with the adjustment and still don't line up quite the way they should. Whether the car has ever been wrecked may be a factor in this.

The 140 has metal clips (that always rust away) to hold the stainless steel molding around the windshield. The late 240s have a different kind of clips (plastic) that will require a bit of figuring to get them to work.