Haven't seen this discussed yet given the TWD news dominating, but as this article states:
"The Walking Dead pinball is one of six machines Stern Pinball has planned through 2015, Dankberg said."
Technically, Stern actively built 6 games during 2014 (Met, ST, Mustang, IMVE, ACDC, TWD), but this makes it sound like 6 new releases (or VEs), no?