In a carbon frame they are press-fitted. In theory, if the frame has no defect, the bearings (at the end of their seat) should be parallel.
It´s possible that frame has some burrs in the area or something that misalign the bearings (paint, resine, fiber…) The normal thing would be to remove the caps from the bottom bracket box and check with a vernier caliper (or better a laser) the measurements on both sides.
like this:
I prefer Shimano PF or BB90/95