Yes, the lowest possible standard, those Nazi-like beanies the HD crowd loves are DOT approved.
DOT is a weak, old US standard in a country where many states still don't even wear helmets.
As for age, technically EPS foam breaks down with age due to ozone exposure just sitting on the shelf. But, I only read this from companies selling helmets, would be nice to see actual testing of NOS helmets 8-10 years old.