How is OEM front badge installed at factory?
 

Front badge fell off.

How is it installed?

A) It is taped on, and the 2 prongs just guide pins.
B) The prongs are friction fit, and hold the badge in place.

If A, what is good tape to stick it back on?

Example from stock photo
https://image.prntscr.com/image/cCam...RVDRItKRzA.png

3m trim tape works wonders.

It's just it's own toyota equivalent of 3m automotive VHB, the pins are guide pins.

I'd use goo gone and/or a 3m eraser wheel and heat and get that area as clean as possible first. Then proceed to reinstall, also the $8 adhesion promoter sponges from 3m make a real difference on how it applies. I've had the JDM badges on my FR-S since 2015 and they show no signs of coming off following that method.

I believe there are friction-fit clips over the pins on the underside of the bumper cover (can make it a bit of a pain to remove). Most people that change badges out simply use the 3m tape.