I bought one of these for my old ranger. But I drove to Kantuckee to have it installed.
The problem was that the company used factory dimensions, but my truck had been in an accident from the rear. The bed was no longer at factory dimensions. So those guys had a time trying to install the cover.
Basically the cover sat crooked on the bed and there was no way to fix it. It seems as though the only logical way was for me to measure the bed myself and give them the dimensions, but they never asked me to do that.
As far as the cover, it was great! Very sleek and the hinges were top quality. Get it painted and it will look even better. I had the lock on both sides.
Concerning locking the tailgate, just shave it and use the lock on the cover. Maybe.