Nice work. I enjoy working on these. What did you do for the silver color? In spray paints, I've used different shades of aluminum and metallic. Actually had good luck with chrome color - while that would be disappointing if you sprayed something looking for a chrome look, it worked well on these.
If you still feel you've gone overboard with the weathering, try gradually misting on some more black in different areas and for different durations until your liking. A little on the grip and back half of the receiver may go a long way.
I've done too much weathering in the past, and reeled it back in that way. And ended up re-weathering some of it after the mist, but not near as much. The end result, I thought, looks like old wear, a repair in the field, and fresher wear.
Nice idea also on filling in the seam, I had not thought of that.
Thanks for posting!