That is a goose egg right? Waterfowl eggs are dirtier usually. My eggs are usually shipped priority mail. Imagine it is all good. I would candle if for any cracks. My call duck eggs I got a month ago appeared to all have broken air sacks, but I still had a good hatch out of them. Good luck!
I do not know what is "normal" but when I have sent hatching eggs (several times now) I send them priority not overnight, however I would never send an egg that dirty. I am assuming that is some sort of water fowl egg, not sure if that makes a difference since waterfowl areas are wetter and muddier then chickens, and I have never had waterfowl.
By the way I was assuming water fowl b/c of the size