I don't know if they've already held off those seats already, but Boheme is always a hot seller for any opera company. It almost always sells out each performance every year at the Met. With Netrebko singing Mimi, it's probably even tougher to get this year.
I was under the impression that each remaining performance is sold out, so your best bet is to try for standing room. It's cheap, has the best(in my opinion) sound in the entire house, and the opera is short.
-There's the muddle in the middle. There's the puddle where the poodle did the piddle."