If your baling sandy soils, sand will get everywhere and premature wear. No way around it. Yes, if you keep the chain oiled, it will attract and hold sand, but if just WD-40, it will just get pulverized or fall off.
Here's the deal between the O-ring and non O-ring, A chain wears more from the inside if non Oring and it will stretch. This stretching is what wears out your sprockets because a stretched chain no longer fits. I would say an Oring chain will last at least twice as long in a sandy environment. Now you have to decide if your labor, trip to the store, shipping whatever is worth it. If you have a long off season with nothing to do, go the cheap route. Some people get a whole bunch of bales on standard chain. But sand changes everything.