I believe the doors are the same through 49-51 though the latch mechanisms and handle splines differ specifically 49-50 and possibly also 51
Outside Door latch and handle and striker area are different on 49. The 50 and 51 are the same. The interior handles window crank and door latch handle are different all 3 years. Picked up a nice NOS set of 49 interior handles just to find out they will not work on the 50. Same outside shape but square and pinned. An old friend of mine once told me that he traded his 49 in on a 50 just so he he didn't have doors that flew open.
I will vouch for that my 49 woody had a bad habit of either door flying open when going around a corner normally giving any passengers a lively experience