I have 4 Brooks saddles, one like yours with the springs, and as a matter of fact - that one is off center just like yours. Never noticed that in all the years I have owned it until I saw your post. So,... I guess it doesn't matter, at least on the sprung model because I never felt anything out of line. The others with no springs seem to be spot on, and one of them is only a year old. I wonder if the tension on the springs is slightly unequal? Not that I can feel the difference, but with no weight on the saddle it could twist the leather a bit. Don't worry about those minor scuffs, a few hundred miles will rub them out and you will probably make new ones leaning it up against things or crashing.