I've had very small doses not show up on dipstick tests. When I was in an IOP program at the very beginning of 2012, I was also taking 0.5-1mg Klonopin / day. The dipstick test they used wouldn't show it as positive for benzos. I've read that about Klonopin before.
But if you're getting a gc/ms test, yes, it will show for Klonopin.
20 days off is fine. You'll test negative.
Klonopin does have metabolites. They're just not pharmacologically active. It's not like Diazepam, for example, in that respect.