^ yes and no. It should get you all the gain you need. But if you were overdriving, say, a vintage amp, while you'd probably get most of the gain you'd need, it'd still not be voiced for metal- you'd probably need an eq pedal, and even then, it probably wouldn't sound totally modern.
I don't think there'd be any of these problems with the FA, since it's modern-voiced, but I doubt it even needs an OD, unless you want it for a solo boost, or just to have more tones available at your feet- I'd try the amp first, sans boost. If the amp isn't doing it for you, you might want to reconsider- an OD is there to put the icing on the cake (e.g. "my amp rocks, I just wish it had a smidgen more gain for solos!"), not make a cr@p amp great, lol.
At least in my view. Other people may (and probably will) disagree, and that's fine too.
:drink: