When I was at Pecos Bill's last October, they did not have cheese sauce at the fixings bar. In fact, I was quite disappointed about it. I asked a CM if they still had it, and he said that I'd have to get back in line and order some, which I did not do because the line was 20-30 minutes long.
So just be forwarned that if you want the cheese sauce, you have to order it now at Pecos Bill's.
The cheese might still be there. I did not notice because I was looking only for the sauteed onions and I was trying to be good about the extra fat and cholesterol. At least they still have tomatoes, lettuce, pickles and mayo!