AB has tried to minimize any obvious tie in to ZigenBock for as long as I can remember. Shiner is a decent Amber colored light lager with a hint of flavor, but it's not really a Bock either.
I've never found an origin story for ZigenBock. I always just figured the marketing folks at AB just couldn't stand it in the 90's because somebody was beating them at something
I'll have to try this just out of curiosity. Of course if you want a known good Kolsch that's also brewed in Houston try Karbach Love Street.