That looks like a RMD I received yesterday from the Exchange -- not that I didn't already have a bunch of them, but it was new condition and came with kydex + tek-lok for $150, which is about the same as a new RMD + KY sales tax would have been without the sheath. It looks like most of the difference in weight would be due to the Res-C handle on the 511.

Edit: I misremembered the RMD color -- the one I bought was tanker, not sage -- I have sage-bladed RMDs, but not that one.