When Red is saying his goodbye's to Gally out the window of the truck, Gally is wearing his hat continuously. Yet, on the last cut-away, Gally's hat can clearly be seen moving through the shot as if Gally is putting the hat back on.
Gally's hat stays pristine through 9/10ths of the movie and it is clearly the same hat. Appears two other hat's were used at the end to show the wear of the night, but these are definitely different (but similar to each other) than the original hat.