I’ve got a rattle in that area and it’s probably my slider or a body mount. Worse in the winter than summer. But I’ve never tried to chase it down. MetalTech sliders for the record.
My sliders rattled for years whenever I had a bunch of weight in the 80. I thought I had a loose fuel filler tube but that wasn’t it. When I cut off my old sliders and installed Slee step sliders, problem was solved. Didn’t even think that was the problem. Great surprise!
When I had those slidersI had a rattle I could never track down (one of many). For me there was minor contact between the slider and the catalytic converter in some instances. My truck has so many rattles now I just embrace it.
The PO really messed with the pinch welds when he installed them on mine.
This might sound horrible to some but I have solved lots of rattles by using those little felt furniture pads as shims in the contact point. One on my roof rack has been there for 3 yeas now and the truck lives outside. Might be a better alternative than bending pinch welds. Pretty sure I have one I my dash somewhere too.