[plain OM]

Is there a front a rear cross member that they might have switched

Yes, they are different lengths; the longer one goes toward the rear. On my cross members there's a small rectangular label at one end with wording to read the instructions, but also a small diagram of a car with an arrow pointing down to the roof. The arrow position is different on each, showing which is the forward and which the rear cross member.

Did you have the cross members on the roof rails before the rails were replaced?