That's the implication. It seems like your argument is based on the premise that all knowledge is tentative, so it should apply equally to every knowledge claim.
In everyday conversation, I think that if I would describe myself as an atheist, people would take that to mean that I'm about halfway between full acceptance and full rejection of the existence of gods, not the reality: that I'm pretty well convinced that god claims are unreasonable, but I recognize that hard solipsism and other issues create a theoretically non-zero but negligible (for most practical purposes) likelihood that every single conclusion I make might be wrong.
If we're being more pedantic, I'd say that depending on the definition of "agnostic" we're using, it may not apply to me. I'm not convinced that the question of the existence of gods is beyond our ability to investigate it, so I don't think I could be rightly called a hard agnostic.