What else do you have? Stock early I-6 engine? Firebreathing 460? Manual trans, or automatic? Overdrive or not? Stock transfer case?
What are you looking to do with it? Hardcore trail riding or daily-driver street cruiser? Or a little of both perhaps?
In my opinion, for all around use, the 37 or 38 option is a bit steep for a 4.10, so figure on changing it out eventually. Plenty of people run them and are fairly happy (I think?), but more often than not, you're going to be wondering where all of your power went unless you go to a 4.88 or steeper gear set.
So, in other words, a change is not required, but you're pushing the limits of the fun-while-driving factor, unless you're running a completely different combo than most Broncos came with.
Paul