It is stamped Stanley HM-6M-S. NOS new in the package. The bag says 61301-235-672 It is metal, candy red and gorgeous.That base number shows a 1968 CB175 model. This piece came from a Canadian collector, so it is possible it is for a Canadian model.
It is obviously Honda, headlight opening 16MM I.D. 18.5MM between the mounting ears, and a CB350 headlight fits right in and the ring fits right over. However, CB350 headlight shells do not have a speedometer opening and they are plastic.
A CB160 sized speedometer fits right in its speedometer opening, but I have CB160 Shells, and this is much larger. This piece will really make your restoration perfect.