>>64082422
It wouldn't have an effect on accuracy because the bullet will engage a non-zero amount of rifling after it passes the gas port. Unlike crimp jump or a damaged crown at the muzzle, is isn't changing either the end state or starting state of the bullet's trajectory, so I cannot see the placement of the gas port relative to the position along the rifling.

However I can see it having an effect on gassing, however trivial