The cheek rest side throws off the nose carving at the comb; on the opposite side there is the patchbox. I think it would be nigh impossible to make both sides the same. You have hit the nail on the head in that you can't see both sides at the same time.
I have never seen a gun with PB and cheek rest with perfectly symmetrical carving/moulding. Similar, yes, mirrored, no.
If you have a small cheekpiece and PB, then you might have room to make both patterns very close.
Acer