Case west you mean?
Case zero came in 2012. DR2 came in 2011
Case west came in 2010.
No. Case Zero was out before the DR2. It is a stand alone prologue. Case West
was add-on DLC that came out long after DR2 was released.
I know first-hand, because I bought Case Zero the day it went up on XBL, almost a month before DR2 came out.
For your reading enjoyment and expansion of knowledge: http://en.wikipedia....i/Dead_Rising_2