I have targeted 4 carbines Underwood, Quality Hardware, Inland, & IBM. The Quality is orig. flip sight, and the IBM is a salvaged receiver, repro flip and repro folding stock. None of them required rear sight to be far from dead center. When I set up the IBM, which has a new commercial barrel, I centered the rear as close as I could and took it to the range (25 yds on sight adjustment target followed by 100 yds.). Right and left were dead on.

My bottom line is: apparently not all carbines shoot to one side.