Comment by monster_truck

I wouldn't be so sure, it's wildly common. Reverse engineering products to figure out how to make them again is its own sub-industry in every manufacturing field, especially anything tool & die.

There's an enormous chasm between when companies started mass producing things and the digitization of blueprints. More often than not it isn't even the original company, it's one of their customer's customers 50+ years after they went out of business.