Indeed, it is a DualUp -- the best display I have ever owned. I love it so very much, I planned to get a spare for when it dies, before they EOL'ed it. (I assumed it would not last long, as there can't be widespread appeal for such a display.) I missed that chance - but after months of setting eBay alerts, I found a local teacher that had a used one with just 400 hours on it (I have 17,000 hours on mine), and I bought it ($50 above retail price) and have it cleaned and waiting in a cloth sleeve for its time to shine, one day.
I talk about it and using it on a Mac with HiDPI display modes in this blog post from several years back:
Technically it's 8:9 so not a perfect square, 2560 x 2880
https://www.lg.com/us/monitors/lg-28mq780-b-dualup-monitor