My Apollo 8 caseback is misaligned by about 10 degrees, not a big deal. But 180 degrees out of alignment shows really poor QC. Things like this do happen, I remember seeing a freshly serviced Patek Philippe in its factory sealed sleeve with the strap put on backwards, the inside of the strap was facing outside. Bizarre, but somehow it got through the final inspection.
The only thing I would be worried about is was the watch opened up post-factory for some reason and the back put on wrong? Is this a brand new watch bought from AD or Boutique?