Smog Pump Decoding.

[Nasblu]

When decoding a smog pump is there any numbers that link it to a specific model of car? I know the casting number and date on the rear cover and The Julian date on the side of the main case. And the various pulleys that are numbered? I have one stamped 008141S I am decoding this as the Jan 8, 1971? What does the 41 stand for? The rear case casting# is 7801149 what looks to be D59 casting date. With a 3927116AU Pulley. Is it possible for a early 1971 smog pump to have a April 5, 1969 casted case? The pump looks to never been apart. Just trying to learn more about smog pump numbers.