I have a Model 10-5, serial # C829XXX, which, according to Supica & Nahas, makes it a 1966-7 model. All fine and dandy. What confuses me is the number stamped on the frame under the grip and on the yoke (302XX). Supica & Nahas seem to generally describe this code as an "assembly #", but then a few pages later list a table of "production codes". Also, 302XX doesn't match with any of the production codes listed (generally in the 6-digit format 1XXXXX). To add to the confusion, the production codes listed seem to be for guns made from 1984 and later. So, my questions are: Do these 2 codes (assembly & production) describe the same thing? Is 302XX a production/assembly code? What does 302XX tell me about this gun?