Bar and counter seats are first come first serve, and yes you can order food.
With that out of the way, this is a very busy spot especially when you've been delayed on the lower C gates (it's located between the higher C gates and the D) I was able to find a spot right away, didn't have much time, was only delayed an hour.
Thy had a pretty good beer selection, will serve it to you in a glass if you want. The server was friendly and talkative as he poured me my pale ale, it really took the edge off, and he was right back to see if I needed my bill, was able to get one more brew down and paid for before my B1-30 boarding group was called.
Want to come back for the pie.