[nittany13]

Often when these card companies become defunct a lot of odd "stuff" from the vaults is released to the secondary market via bankruptcy auctions years later. I bet a large majority of those cards in question that you are referring to were most likely "extras" kept in storage at the once respective operational card company plants. If you pulled one of these unnumbered (which are supposed to be numbered) cards from an actual pack I would think that would be highly unusual.

I for one hate these types of "irregulars", but that is just me.