No, I don't *think* that it's actually backward - I believe it was intended - when the lever is "on top of" the red F, the green S is "uncovered" and showing, meaning THAT is the state it's in (Safe). Meaning that the one covered up is not what state it is in, but the one exposed and easy to read.
And conversely, when the lever is "on top of" the green S, the red F is "uncovered" and showing, meaning THAT is the state it's in (Fire).
But I can see how you could interpret it the opposite - is that what is happening? I could be wrong.