Yes, Metuchen had the markings on the passenger side of the radiator support. They were usually painted over like Dearborn cars. Rotation number usually found on lower front cross-member (piece below radiator support). Otherwise, paint-ok stamps on fenders, cowl and sometimes the bottom of the hood, maybe a different format or design.
I've also found a hook number for the fenders on the frame rails, behind where the front bumper brackets attach.