Personally I have never liked the heavy weathering on guns. It just looks wrong, and weathering like that, would never happen on a real gun.
I have had some really beat down guns in my hands, but none have looked like that.
If you want heavy weathering, at least concentrate it around all the "moving" parts and edges. Thtas where weathering like that will occur in real life
Maybe add a scratch or two here and there on the barrel/receiver, but nothing more. Otherwise, I love the detail you have put in to this. Absolutely awesome