Rob,
Just about every 4:10 CRW coded rear I have seen has had a yellow paint 'blotch' on the top of the nose area of the center section, a yellow paint dab marking the location of the vent tube, a blue paint stripe near the right side shock mount (under the black paint) and an "X" on the rear end cover to name a few. Dennis C. and Dean R. both have good photos of their cars showing these same markings. I don't recall seeing any numbers written on them. By the way, your picture did not show up.
Rick