According to Wikipedia, the term comes from the soda, not the other way around. But if you saw specific references to, and even bottles of, the soda, then in a discussion of knowing about the soda that fact completely overrides the question of knowing the term - though that is interesting for other reasons.

As I noted, I certainly knew the term, but I had had no idea it was also the name of a soda, even though I read MAD Magazine for a while. (It had tamed and became less NYC wise-cracking by the time I got around to it.) Even Bored of the Rings didn't say specifically it was the name of a soda; only the pairing with Pepsi, which I did know about, clued me in.