Generally Gen 2 would refer to the 1.0 (though they were never called 1.0, as that's a retroactive name), since the 2.0 didn't have any generations. But it wouldn't be uncommon for someone to say gen 2, and mean the 2.0. Generations are a community driven term, as Oakley has never cared much as long as the products didn't co-exist on the market. Even Jim Jannard when he posted here called the New M Frame (the one still around) a Gen 2, despite being in the same boat with the original version having 2 generations. We've had to invent and define most of these terms, and it makes some portions of the database a little tricky to organize.
Visually it may be best.
E Wire Gen 1
E Wire Gen 2
E Wire 2.0
E Wire 2.1