Are we sure any and all alterations must have happened at the factory? There's a sizable cottage industry is altering molds without them being "faked" deliberately by some nefarious profiteer (Why you would try to counterfeit a Lyman mold is beyond me). We also have professional services by more established players like Erik Ohlen. What piques my interest is the lesson gained from a customer of high-end tools and machining equipment over 30 years ago. It would not be cost effective for a firm like Lyman, RCBS, SAECO, etc to "redo" a mold from the scrap box. Most likely there would be no scrap box for such reclamation. If somebody messed up a product, simply grab a new set of blanks and start again. My guess is an aftermarket alteration.
But these may also have been handmade molds from the '30s, and this IS Lyman...