HELP! I think new flowmasters are on wrong!

I have this mechanic and was in a hurry to finish my exhaust job. I bought flowmaster original 40 mufflers, and he put one muffler with the inlet going to the motor and the other one with the inlet going to the rear end, it sounds bad. is the flowmaster mufflers suppose to be put in that specific direction as stated on the casing of the muffler?

Inlet is just that, inlet. He put one one backwards from your description. I'd be sure to go back and have them correct thier mistake.