The Grillstravaganza board that shows sales after Hank returns to fix all the problems at Strickland propane, shows Hank with no sales, Joe Jack with 8 sales but 4 of them removed, Enrique with 3 sale, Maria with 2 sales and Bobby with 4 sales but 2 of them removed.
Then when the last customer comes in, the board reads Hank Hill with 8 sales, but 4 removed, Joe Jack with 3 sales, Enrique with 2 sales, Maria with 2 sales and Bobby with 4 sales, 2 removed.
The first board was correct.
The sign above Thatherton's repeatedly switches between inviting customers to meet "the girls from Jugstore Cowboy" and "the Hooters girls", depending on far it is in the background.
The "R" in Maria's name on the sales board repeatedly changes shape, resembling an "R", a "B", and an "L" at various times.