On the top picture I think it may have been a shipping type thing. A bunch of machines have that hole but I have never seen anything screwed in the hole. I think if you push the latch down to lock it in place the hole will line up with the slot so if a screw is in the hole it can't lift.
The bottom picture just has a screw and a washer. You add/remove washers under the tab to raise or lower the light panel and the screw and washer on top just keep it from lifting off.