Not at all. I buy figures that I think look cool, whether I know anything about the series they're from or not.
This is why I've got several Queen's Blade figures (
Risty,
Shizuka,
Siggy,
Tomoe) even though the series is trash, and I've got a
Yamamoto Isoroku that's from Sengoku Rance even though I'd never heard of it before.
(True story - when I bought this in Akihabara, my friend in Japan wanted to see it and he exclaimed "Oh! That character's from that hentai game!" We were in the middle of his office and surrounded by all his co-workers at the time. He quickly tried to follow up with, "I, uh, haven't played it but I hear it's pretty good." Sure, buddy. Sure.)
I've also got several Bleach figures too, and I've never seen the show.