Doesnt matter where ya get them, they are all made by DEPO, the same company that made your stock headlights. DEPO also makes the new one piece headlights.
When I saw that allen / hex screw, I took it out and took them to lowes and found me some phillips head replacements. To heck with that hex crap.
Yes, seal them well, and dont ever take your truck to a pressure washer. They seem to be good, as long as you dont go through a pressure washer. For some reason, that breaks the seals. Also, for the turn signals, you might want to pick up some sylvania corner bulbs. These are blueish / purple when off, and then light up amber when on.
~CYCLONE_06