I am 99% sure you do not have night sights.
Darn. Anyone have a sight pusher I can borrow?

I am 99% sure you do not have night sights.
Different as in "won't fit or work correctly on a 5906" frame, or different as in "doesn't look like a 5906" slide?
(I appreciated your other tips on model numbers to search for.)
Gen 3 sights can be very difficult to remove if you don't have a sight pusher. Also, once relamped, you don't really want to install with a punch and hammer. Consider sending them the slide. Insure it for enough to replace it.
On a related question -- on sight #2, who makes the tritium inserts? My 1076 night sights are very dim (bought it that way) and I would like to send the slide in to have them re-lamped.