GM uses primer.
Many older Ford trucks didn't use primer, they were suckered by a paint company that stated their paint did not require primer. I believe these were for trucks in the later 80s, early 90s. Not that familiar with the problem, but had a paint guy at GM explain the problem.
There is no sound insulator on the H3, doesn't seem to need one from what I have heard. As for heat, you bring out a good question.
I guess you could purchase one and attach it, or just hope that the testing indicated it was not required.