Ring out the OEM connector and then identify pin 3 (tail lights/parking lights, +12V when you turn them on for the truck wiring) to get the proper orientation. Label the OEM wires with tape and markings. Then just match up with the wiring diagram with that Hopkins part. Solder AND secure...
That specific area is known to rust at the lip where the windshield sits and mates to the OEM windshield seal. You can try dropping that corner of the headliner and gooping the crap out of everything, but the rust will continue, and the gap will probably grow.
Buy the $250 Schwaben diagnostic tool and get button cover protectors. Best to immediately bond with the tool (perhaps some tender cuddling and caressing) since you'll be using it often and it will save you $$$$ in the long run.
It is a shame it got to this point, but let's not lose sight of a key statement made by the vendor, that if in fact true, speaks volumes to me.
The vendor offered to provide a refund before installation, and the buyer refused and proceeded anyways.
Let this be a lesson to all by quoting Sam...
Yes. as long as you also have the appropriate bracketry to mount to the OEM mounting points inside of the dash.
This is true, but it is flat on the back side. It would be trivial to buy a single DIN cover and sticky tape or glue it in the right spot.