Hi, I didn't quite understand the 'parts coming out of the housing' thing, but maybe I can answer you anyway. The fans can be mounted either one way or the other. This depends on the direction you want to give the airflow. To create a good air circulation inside the case, you have to mount fans that draw cool air in, from the outside to the inside, and others that push warm air out. Fans mounted in one direction draw in air, and in the other push it out. In any case, they must both be mounted in the same direction, that goes without saying! ;-) I hope I have been helpful!

So one blows in and the other blows out in a mirror image? That would definitely not be correct.
But if it is "mirror-inverted" so that both blow air in the same direction, that would of course be correct, but in the former case the fans would have to be mounted completely differently.
In this case, simply rebuild the incorrectly directed fan.