It is certainly possible that Hal Finney was using a figure of speech or employing a bit of literary license when he referred to his Bitcoin keys being stored in a safe deposit box. It is also possible that he was using a metaphor to describe a secure storage location for his keys, rather than describing an actual safe deposit box at a bank.

Without more context or further information, it is difficult to say for certain what Finney meant when he wrote this. It is worth noting, however, that people often use figures of speech and figurative language in their writing, and it is not uncommon for them to use phrases in ways that might not be taken literally.

In any case, the fact that Finney referred to his keys being stored in a safe deposit box does not necessarily mean that he was Satoshi Nakamoto or that he was not Satoshi Nakamoto. There are many factors that can influence people's beliefs about who might be behind the pseudonym, and a single phrase in a forum post may not be sufficient to conclusively prove or disprove someone's identity.