By all means call them, but I believe most upper end helmets have the area reinforced and the screw inserts already installed, which makes a lot of sense rather than run the risk of the buyer yanking out the liner/padding and drilling holes.
The EPS is basically Styrofoam, covered by fabric (nomex?). The padding is best if it does not rebound, causing more brain injury, and helmets in hard hits are one time use.
If you wreck a car at an NHRA race, two things happen immediately. They pull the cert sticker off the chassis and they pull the Snell sticker out of the helmet.
