Snap rings are fairly easy to find, most automotive stores have an assortment, even ACE probably has what you need. You don't have to be all that accurate and I'm at work so I can't get a quick measurement right now, but close counts and they are inexpensive. Probably less than a dollar.
You might not need one, but they are there for a reason. I had one pop off my Trooper. The axle shaft backed out and I ground the end off the axle drive shaft and had to replace it. The Jeep isn't set up in the same way as the trooper, but why risk it. After all even spending $6.00 on a snap ring is cheaper than $100 on a new axle drive shaft. Seems like a penny wise and a dollar foolish way of thinking to me.
A word of advice, you will notice that the axle drive shaft is hollow, if you look you'll see that it is threaded. When installing the snap ring the shaft usually will move in and you can't get the ring on. Thread a bolt into the shaft and pull the shaft out to get to the snap ring slot.
By-the-way, you shouldn't have ANY parts left over after working on any vehicle, that's bad. A $0.05 part can easily end up costing thousands in repairs.