i think it's much harder to identify a 45 "tax scam label" as there were so many tiny labels, who knows what the motivations of the owners were. probably most legitimate labels were tax losses.
also, 45 labels don't make as much sense for "tax scam" because the whole point is to pretend to lose as much money as possible. If you get ahold of some random old tapes and release an LP's worth, you can claim all sorts of studio time and other costs for all the songs on the LP, press it up, instantly cut it out, and get the loss. a 45 doesn't have as much loss. I've read that article before, i think the dellwood inclusion is just sort of random. either way, the acid archives has a whole section on tax scam labels.