You imply that Satoshi neither relied on hashcash and b-money as example for what became known as Bitcoin, right? That makes his invention of Bitcoin even harder to understand, since he is not relying on historical solutions that could have led to Bitcoin.

But to answer your question, no, I did not hear about hashcash before I heard about Bitcoin. I think that is because Bitcoin, vs other solutions solved everything needed for a decentral monetary system in "one go".