Couldn't say how warm the golden rod gets, it feels warm to the touch but nothing you couldn't hold on to.
An option if you can't bolt it to the floor is too bolt a piece of steel to the bottom large enough to keep it from fitting out a door.
Keeping the guns in the cold shouldn't be an issue. However, getting them warm/cold may cause them to draw moisture.
Good Luck with it.
He who dares wins.
NRA Life Memeber