Boy, were they ever...
The company basically added or dropped players as they went in and out of the majors. So, the Gehrig card is the key SP--obviously, 1939 was his last year in MLB. Gabby Hartnett is another really tough card; he was out of the majors in 1941. Johnny Rizzo has bedeviled a lot of us--a goner in 1942.
The players with multiple cards had changes to their cards for some reason; the tougher ones are SPs from limited time frames.
Also bear in mind that the cut-off dates between the salutations and the later cards are really random. If a player lasted past 1946, his salutations card was sometimes printed well into the purported run of the 1947-66 issue. Ted Williams, for example, had his common salutations card printed into 1960.
