The brand-name on the box has little relationship to the factory (or even the country) that makes the part.
While this is true for heaps and piles of consumer goods, it was popular with automotive items--entire cars, and the replacement parts to support them--long before it was a big deal for other mainstream products.
Forty years ago, we called it "Reboxing". As an example, there were four companies making hydraulic lifters for Chevys, and a hundred companies that bought in bulk, put the bought-in parts in a custom-printed box, and passed them off as their own.
I would expect that when GM allows a change to a part--replacing brass terminals with aluminum, for example--they'd also issue a revised part number. I remember seeing thick paper books--3--4 inches thick, sometimes more--showing the part number history--the original number, superseded by a new number, sometimes multiple supersedings. The final number would either be the "current" part number, or the final version that was then discontinued. Seems to me the book also had the last-known price for the part.
As said, the typical problem with Vortec caps is that they've got the conductors molded-into the plastic, crossing over each other.
IF (big IF) I had repeat problems with Vortec caps, among the things I'd be looking at are plug-wire resistance, rotor-to-cap gap, and spark plug gap. Extreme resistance, or large gaps drive the voltage of the ignition system sky-high, making life intolerable for the ignition system insulation--including the plastic of the distributor cap.