That will definitely depend on the vinyl - that 3.5 mil figure is the vinyl material alone, not including the protective backing material.
I can tell you this - 3M's 1080 material can stretch a fair amount with some heat applied, which will certainly make the vinyl a bit thinner. However, I don't think it becomes materially thinner. that the air release channels do not completely collapse during installation. 3M's 1080 is significantly more pliable than Di Noc. That being said, you can get some surprisingly convincing textured finishes out of Di Noc thanks to the thickness - there's a burl wood vinyl that looks way better than it has any right to!