In the absence of anyone else chiming in, I'm going to say that those markings belong to the steerer tube manufacturer or wholesaler, not the assembled fork. I think we've had it confirmed before on this site that fork production was not recorded like frames were and that there definitely is no fork book.
The box crown forks used steerer tubes manufactured by Columbus that have rifling on the inside in the area where the box crown attaches. Very similar to a gun barrel. Supposedly increased rigidity without a big weight penalty.
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