I have a hard time believing this. How is a non-RIAA equalized record supposed to be played? All palyback equipment/setups have built in equalization that converts the RIAA equalized signal from the vinyl back to normal. It's either built in to the vinyl player, or done via a phono-preamp usually in the amplifier or a mixer. This isn't usually explicitly stated anywhere on the equipment as it's an industry standard.

So if you have a record that doesn't have the RIAA curve applied, what are you supposed to play it on? The RIAA correction is pretty much unavoidable on any standard playback equipment.

EDIT: I'm willing to believe this if you can reference me to some example of modern non-equalized/non-RIAA vinyls.