Star usually announced the print runs for the limited sets, and/or included them in the packaging like that. A third party would have just gathered that information 2nd hand. All these years later, with fancy foil stamping and whatnot, Star's method of providing that information seems very casual. Classic was no better in the years that followed, with their "limited" print runs of 600,000 draft pick sets where the serial number was on a paper certificate included with the set, or part of a sticker on the box.
I wish Star had run ads in the hobby magazines at the time. I never knew what they produced until I saw it at a card show, or it was listed in another dealer's ad in a magazine.