quick dumb steering question

[bdegs]

So I didn't pay attention when I pulled the steering box off my truck and long story short, I have 3 boxes sitting here without arms on them and have no idea which are 2wd and which are 4wd. How can I tell? The only labels I see stamped in the side are 4 or 4L.

???

 

[NorCalKid]

the 2wds have a threaded section and a nut to hold the pitman arm on and the 4wd are keyed and the pitman arm tightens around the sector shaft

 

[bdegs]

Perfect thanks! Looks like I have 1 4wd and 2 2wd. Thanks again!