Bought a new tailgate for my truck installed it/ locking system everything is great.

However to put the tailgate cap on tailgate you can :
1) purchase specific tool from Gm ? To attach rivet nuts to tailgate. They end up being squished and pulled or pushed through the metal on tailgate. ( this is by design) Then put cap on and screw bolts into holes provided -> then into rivet nuts.

2) I’ve seen few DIY ways to do this online - there are a few that look like they work;

However i am slightly concerned about attempting the DIY way don’t want to mess up my new tailgate.

My question is this - does anyone know what the tool is called to attach rivet nuts ? To tailgate.
I call them rivet nuts but not exactly sure this is what they are called.

Depending on tool price I may purchase .

Any advice or URL’s to sites that can help would be welcomed.
Thanks !