Question on 2008 Goudey Baseball Base Set

Terry Jackson

Hi all. I am sitting here sorting some 2008 Goudey baseball base cards and noticed their are two different backs: one printed on light gray stock and the other printed on a somewhat darker gray stock. Is the darker gray stock considered to be a parallel set? I did not see a separate checklist on Beckett.

Any light you can shed on this would be great...:) Thanks...Terry