Just wondering. not sure if the books ever address this. I know he hooks up with the brotherhood w/o banners, but do they know who he is?

Sorry, just reading book five and I'm rethinking about previous characters. Thanks!

I don't think yo. At least the chapter in Feast where Brienne sees him would suggest he has no idea. (He could faje his innocence in this matter, but it wouldn't fit for his character.) And since she is kept from telling him, he still won't know.