Here's an odd date stamping. It's "bG", lower case "b", upper case "G". One instance is an oddity, two are a trend. I interpret that as "6G", and assume the number "6" was wearing out and, as the end of the production year was near, the letter "b" was used as a "6".
Stamping on license plate lights was not totally consistent. Most are on the frame in the location where the "bG" is located, some are on the opposite side, some are a single letter, and some are missing (I can't show you those, they're "missing"). Each assembly had the appropriate Ford logo, SAE markings and correct wire.
Jim