How do you mean "sweet?" Do you mean it like, "Aww, that's so sweet you guys!" Or, do you mean it like, "Dude that's a sweet guitar you got there. Fuck, dude is that a Les Paul? Fucking awesome, man. Wowie zowie."
'tis. And no, I've never used "sweet" in that context before. I also had a feeling someone would ask this question.