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.