Yeah, I was called to go west and watched it pull into Cheyenne while waiting for my train to come in.
I saw all the equipment sitting there for about a week prior to the trip. Yes, it was a really impressive train. All of the equipment is UP owned and operated.
No, it's not everything that UP had, there were an additional 4 or 5 cars (Sleepers) stored on a side track known as the Wool House when 844 made the trip.