Cal. Code Regs. tit. 13 § 636
Markings on the housing of an original equipment lamp or reflex reflective device which is factory installed on a specific motor vehicle model shall be visible when the lens is disassembled from the housing or the device is disassembled from the vehicle. Markings on original equipment housings or mounting rings for a sealed optical unit shall be visible when the unit and ornamental trim are removed. When removal of the lens from the housing would destroy the device, the housing is not required to be marked. Housings of separate control or power supply units (such as for reserve lighting and outage indicators or gaseous discharge warning lamps) shall be marked so as to be visible when the unit is installed on a vehicle.
Cal. Code Regs. Tit. 13, § 636
Note: Authority cited: Section 26103, Vehicle Code. Reference: Sections 24006 and 26103, Vehicle Code.