Also, how did you identify the screens? CTRAging? Because I thought at first that my 3DS has dual-IPS screens (because damn, it's literally looking very good, and the image quality is awesome, and (compared to my phone) it genuinely looked like it was IPS)
(I'm lazy to delete the above message just to edit it, so)... but CTRAging says that I have double-TN screens. But I don't care, because the image quality is pretty rad
Oh you can tell by looking at it with the naked eye. I got two New Xls, one has two TN displays while the other has dual IPS displays. The image quality and the viewing angle is amazing!