As I'm sure many are aware, when determining "silencer" status, the BATF has latitude so broad that they can pretty much determine anything as such.
The shroud on the Marauder is basically a sleeve that runs the entire length of the barrel and is threaded internally at each end. What goes on inside is currently unknown to me.
The key is to not force them into making a ruling on something below their radar, within reason. What I mean by that is if it looks like a silencer, and can reasonably be made to function like one, you might get in trouble for it.
If it doesn't, and can't, don't push the issue by demanding a ruling on it anyway. You probably won't like the answer.
Pics are easy. Google Benjamin Marauder. I don't have any yet.