The part in the movie where all the guys need a place to sleep, they make a deal with the manager and he says that room is number 126. When the guys enter the room a little bit later the number on the door if you can see is 6!
If you look closely at that part you can see that it looks like the numbers fell off. The six is about to fall off. Also look at the condition of the motel its RUNDOWN!!!! THIS IS NOT A SLIPUP!!! This is just you not paying attention.