The idea of electronic money is old. What this describes is a Chaum blind-signature style centrally-cleared coin, which dates back to his 1983 paper. There is no protection against double-spends in this scheme (without the clearing agency taking an active role), and no protection against the central agency creating unlimited amounts of coin.

Proof-of-work schemes like hashcash and bitgold are much closer to hitting on the central ideas that led to Bitcoin. It's like crediting Democritus with atomic theory -- yes, he's talking about the same thing, but in such a way that the final realization is so different as to be unrecognizable.

Satoshi Nakamoto referenced Adam Back in his Bitcoin white paper. I don't see that as Adam Back ‘trying to take credit’, rather the reverse.