There is a difference in Wikipedia between "hip" and "hipster" but I suspect that would be cleared up with an edit. "Hip" means "in the know" as in part of a sub-culture. The definition of "hipster" as used in the 40's as a jazz aficionado and etceteras (as someone above has posted) would have been the use within the jazz community and there were certainly other sub-cultures that were self-defined as "hip." The zuit suit crowd would definitely have been self aware enough to consider themselves "hip." This distinction would have indicated that the wearer of the zuit suit was aware of the political message he was projecting. There is no question that wearing a zuit suit was a political act since there were moves to outlaw zuit suits in Los Angeles and war times Federal acts specifically called for slimmed down suit profiles. Zuit suits were seen as both the target of these acts and it was a response to perceived oppression by zuit suit wearing latinos to continue to wear them. All of this comes from reading the wiki articles about "hip," "hipster," "Zuit Suit," and "Zuit Suit Riots."
With a word like "hip" you have to read between the lines. Even if the zuit suit wearers did not use the word "hip" (since many of them probably did not even speak english as their first language.) they were in fact hip and hipsters because of being aware of the political nature of their actions as outsiders. This is a distinction I choose to make, you may not feel the same way, but I believe that it is consistent with the historical usage of "hip."