Now I would like you to know, that this is from an ancient purchase from Humble Bundle, but unless Steam can somehow see what you purchase on humble bundle before you even try to activate a key from there for a game you already own, then I have no big reason to suspect the key doesn't work.

Nonetheless, I would appreciate it if you agree to cancel the giveaway should the unexpected for some unexplained reason occur.
Thanks and I hope you are having a great year so far.