This is what Beckett Online has for this set:
"This grouping encompasses a wide time span but displays a common design. The following players have been illegally reprinted in mass quantities on a thinner-than-original cardboard which is also characterized by a dark gray back: Aaron, Ford, Fox, Hodges, Elston Howard, Mantle, Mays, Musial, Newcombe, Reese, Spahn, and Ted Williams. Each card measures 3 3/8" by 5 3/8". In the checklist below SIG refers to signature and SCR refers to script name on card. The abbreviations POR (portrait), BAT (batting), and FIE (fielding) are also used below. There are many levels of scarcity within this "set," essentially based on which year(s) the player's card was printed. The Mickey Mantle portrait card, for example, was only printed in 1966, the last year of production. Those scarce cards which were only produced one or two years are noted parenthetically below by the last two digits of the year(s) of issue. Cards which seem to be especially difficult to obtain are the ones produced only in 1966 which are the aforementioned Mantle Portrait, Ford, Kranepool, Richardson, Skowron (White Sox), Ward and Yastrzemski. Some leading exhibit experts believe that the salutation and these cards should be checklisted together because of the long printing history of some of the salutations. Please note that the following cards have been reprinted: Hank Aaron, Whitey Ford (no glove, throwing), Nelson Fox, Gil Hodges (Brooklyn cap), Elston Howard, Willie May (Batting, New York), Stan Musial (three bats, kneeling), Don Newcombe (Brooklyn cap), *** Wee Reese (ball not visable), Warren Spahn (Boston)."
Hope this helps!