102's on a Pete 579???

I drove a Peterbilt 389 just like in your situation there were no Fasteners available and there was no location I was able to attach an antenna so I had to think outside the box and create a solution to the manufacturer's
problem. The fairings on the rear of the cab had a split between the upper and lower part and a flat piece of stainless steel fit right into the split which is where I mounted my dipoles on that particular truck. All I had to do was drill a hole through both layers of fairing on the inside where nobody would notice and put a single nut and Bolt Sandwiching the stainless plate between two layers of fiberglass. When I turned the truck in all I had to do was leave the nut and bolt through the hole minus the plate and my employer was none the wiser

 

It was an awesome match I think I was around 49 ohms and the SWR was 1.3 or something similar and reflection wasn't an issue because it was a plastic body.

 

At the time the Peterbilt 387 and Kenworth T2000 were the biggest problem trucks for setting up antennas. Probably fairly similar to the Freightliner Cascadia nowadays

 

If the body is made out of aluminum then you can scratch that dipole idea