Lionel,
If the mufflers are the correct part numbers, and the pipes are the correct numbers, and the mufflers are installed correctly, you shouldn't have this problem.
Somewhere along the line, either your mufflers or pipes have either been installed incorrectly, or something has been modified to allow this incorrect installation.
As many planes as there are that are currently flying like that, it must not be causing any problems. Also, there must be a lot of IAs allowing this condition to pass. That's their business and I'll stay out of it. But, when it comes to matters of the powerplant and exhaust, I'm pretty picky.
Unlike some other IA's, I don't get real concerned about little things unless it affects flight controls, engine and engine controls, or structural integrity.
Bottom line, Lionel, I'm not aware of any configuration that left the factory with backwards facing exhaust stacks. If yours are that way, something isn't correct.
