Where did you get that info? If you're correct, then my September 1968 P&A 34 is wrong. It lists the 3893814 as being used on small blocks with A/C. (There no mention of Big Blocks with A/C.)
My P&A 76 (1946 - 1976 Dealer Parts and Accessories Price Schedule) also has BOTH part numbers in it!! Usually, when a part is superceeded, they remove the original part number.