Ended up drilling through the rivets with cobalt drill bits, finally they're off:
Put on the Miller CAT stiffeners that were recommended and yeah they feel well made and fit easily, thanks all!
I figured it out, these have nothing to do with the tailgate. I think this truck was fitted with the bed extender which I didn't get when I bought it and these are the brackets for it. I already ordered the Miller CAT stiffeners, oh well...
I have a smartcap and a rooftop tent installed on my tacoma so thought to get bed stiffeners installed to avoid having the sides of the bed sag over time. I got the Cali Raised stiffeners online but it turns out they can't be installed when the truck is equipped with a power tailgate, since the...