Yup, they are rebranded Tencate plates, which that part I like for Tencate makes some great armor. What I don't like is their "duritium" BS. They say that is why their plates are lightweight is because of duritium. Looking closer, their ceramics are lightweight, for they do not have edge to edge protection. A 10x12 is an 8x10.
Adept armor seems a dubious to me, I am not 100% sure about them.
Yeah, the Duritium appears to just be fancy branding. I was once told that you can ascertain the legitimacy of an armor company by checking out their physical address, and shotstop's listed business address doesn't look remotely large enough, IMO, to be an R&D facility for exotic "Duritium" manufacturing and testing. It's situated on commercial property between a software store and an electronics seller. (https://www.shotstop.net/pages/contact)
It does look large enough to be a location capable of shipping rebadged plates and office work. That fits.
Meanwhile, according to google street view, Adept's listed business address in Oklahoma is just an unmarked garage right next to what appears to be a paint store in an industrial park. (https://www.adeptarmor.com/contact/). Their "European facility" isn't listed on that page. Not sure what's going on there.