sure are, drill out the rivets at the rear, pull the end cap and stinger tube out, clean out all the bad packing, replace with new, re-rivet or use short hex head self tapping sheet metal screws with a little high temp rtv on the threads to keep them tight.
Just got done shortening/repacking my FMF silencer. It is held together with bolts, making the repack all that much easier. I used the FMF 2 stroke packing. Can't go wrong for $8.