Rachets, are you sure that the two yellow wires don't go to a fitting that snaps into headlamp assembly? The fitting might be covered on the back by a flexible rubber cover and the fitting might hold a tiny bulb? Like for a signal light?
In these days of one size fits all after market parts, it is possible that some cars need the sticker pulled off of the hole so the fitting can be installed and other cars don't use the hole, so it is sealed to keep dirt and moisture out of the headlamp assembly.
Last choice would be that it's the wrong headlamp assembly. It happens. Even when the book says it's the right part, it may not fit. I've had this happen with certain brands of belts. And with a bolt from the dealer. The book showed a bolt that was about an inch and a half long. I needed a bolt that was about five inches long. Because they couldn't figure out what the part number for the bolt was, I had to scrounge one up from a junk yard.
Since the screw head for the adjuster mechanism mount looks like it has a bit of rust on it, I wonder if you have a made in china part. Sometimes their engineering leaves something to be desired.
What do the yellow wires power? If the fitting is fused to the housing and it doesn't really serve a useful purpose, can you just disconnect the yellow wires at the wiring harness and forget about it? A design change over the years may have removed whatever is attached to the yellow wires.