From his statement in the article, I think what the DA meant was they were mostly "real" cars as opposed to clones or fakes.
This is interesting in that seized cars that are auctioned off usually don't bring a lot of money. Sometimes the agency auctioning them off barely breaks even between what they make and what it costs to auction them. These are different. The DA's office, as well as whatever LE agencies were involved, most likely made a decent amount of money, even more if the cars were real.
Unfortunately, it's quite possible that a real car could end up with a state issued VIN, and the decrease in value that comes with it. In some states, once a VIN plate is removed, the law requires a state issued VIN be affixed, regardless of the authenticity of the vehicle. I haven't been able to find that stated in Oklahoma law, though what I have found seems to lead in that direction.
Whew, talk about going down the rabbit hole!