My guess would be the cards of the player that show the MLB debut date in foil on the front are the ones that are not designated as RC.
Collecting John Stockton, Karl Malone, Ivan Rodriguez, Gary Carter & UF player rookie year cards. Plus Jedd Gyorko rookie and prospect cards.
Jedd Gyorko 2010-2013: Have 329/419 including 1/1s
Wantlist: http://sites.google.com/site/sportscardsite/set-needs/
Jedd Gyorko 2010-2013: Have 329/419 including 1/1s
Wantlist: http://sites.google.com/site/sportscardsite/set-needs/