That's right-side up. The real HP rack rails have tabs that fit into slots that stabilize the rails in a belt-and-suspenders fashion:
Can't say that I've ever seen a Teflon screw used to mount a rack rail before, but I'd sure want those tabs in place if I did...
Yep, I have some rails that have those tabs that hook into the slots on the sides and they do sit that way. However, that rail in the photo is upside down. They were like that in the rack when I got it and yet the gear didn't line up with the HP rack holes on the ears until I flipped them.
I suspect these are either '3rd party' rails or HP changed the layout in the later ones.
I prefer these ones with the tabs to be honest.
TonyG
BTW thanks for your GPIB toolkit really appreciate your work there.