The reference was in an earlier book:

 

Mat: Are you related to Jain Charin?

Noal: ...A cousin.

AHA!

Funny how that conversation automatically turned him into Jain Farstrider for me personally, I completely forgot about the cousin part xD.

you know, i'm going to say yes he did know

why you ask? well i don't know, but i just always assumed noal was jain farstrider even before the whole towers scene. i also vaguely remember there being reference to it, or a conversation about it in one of the previous books.

i'm actually in the process of re-reading the series so if i come across it i'll be sure to update this post