I replaced the screen on my iPhone 8 with one of those cheap digitizers you can get on Ebay or Amazon. There's no way to tell from looking at the body or in iOS settings.
What you can see is that the screen sucks a whole lot compared to the original. Colors are enough off that it's obvious…at least when side-by-side with an original.
If it had been the equivalent of the original screen I don't think I'd be able to tell.