The best shot I could find of her actually using the system was at 8:20, and it looks to me like an ordinary 5170 AT with what is probably a PGC, based on the appearance of the CRT and the image display characteristics. It's possible the AT (given its processing abilities relative to '92) was an administrative terminal rather than the main graphics system, but given the probable PGC, perhaps not. Early on there's a wide shot with a PS/2 8560 or 8580 visible. The show implies the software is probably a PRPQ.
The monitor has grey knobs so it's not a 5153 because they have black knobs so that's a 5154 EGA monitor at a bare minimum. EGA did support up to 640x350 in some video modes so it's plausible that that might be EGA.
They are indeed almost externally identical, but the 5175 is an analog monitor almost-but-not-quite compatible with VGA. (It runs at 640x480 at the same scan rates, but I think it uses composite sync. Apparently adapters did exist.) I kind of wonder if that's a 5175 plugged into some other kind of graphics card because the PGA wasn't really optimized for paint-type programs.
It's theoretically possible, but would be odd given IBM's involvement. I did a desultory search to see if any public records pertaining to the project are online, as happens sometimes, but didn't come up with anything. So probably we're going to have to live for now in a world where we can only guess.
I don't think IBM would object to using a product they didn't make if it was something that filled a niche they didn't have an alternative. What makes this a little tricky is that some of the equipment in that video is clearly newer than a 5175 (the PGC was discontinued when the PS/2 line came out), and in that era there were better-than-EGA third-party options out there that could drive the 5175.
The real reason for thinking it might be something else is simply the fact that software support for the PGC was absolutely dreadful and the card was, by design, really bad at raster graphics, but, who knows. If it's running some completely custom thing that IBM wrote for it that might explain why she's stuck using the AT and PGC when there's newer equipment sitting there at hand.
I don't know any details about this project, but perhaps the AT was upgraded over the years. Matrox as well as others built PGC compatible cards. They were supersets of PGC. Perhaps there was a requirement to maintain comparability with PGC instead of VGA due to software or non technical reasons. If the project required a CAD/high-end video card, IBM with its MCA, would have far fewer options.
PS: What is it with that description of the guy? It gets a bit specific, lines up cigarette butts in rows? It sounds more like a novel. LOL