I don't fully understand your question but....
you can see this set in the Getty Design catalogue here:
Coachwork Fenders and Flares | Getty Design LLC
The are called "GT2 Fender Flare Set."
The front flares have flanges and indentations which you can see in the picture. So you can use button head machine screws, or fill in the indentations and come up with a different way to affix them.
The rears have flanges, but do not have indentations.
Lots of ways to affix these things.
I am pretty sure that the flares on the '74-based turbo in this article are the Getty GT2 parts:
CENTER STAGE> Hwy 341 Hillclimb Hero Porsche | MotorMavens • Car Culture & Photography
That owner/driver is a friend, and I think his bodywork is from Getty Design. You can see he modified the front flares for wheel well air extraction. And he modified one of the rear flares for air intake. He uses machine screws for his rears.