I wouldn't be able to say about a washer, I've heard that theory being tossed around for a while.
I think that the zoomed in image isn't showing a casting seam, but instead it's paint from the top of the grenade section lining up with either paint / shadow on the lower windvane section and *something* on the upper windvane. I would guess that it's just weathered paint, but it's hard to tell in that image.
I think that the zoomed in image isn't showing a casting seam, but instead it's paint from the top of the grenade section lining up with either paint / shadow on the lower windvane section and *something* on the upper windvane. I would guess that it's just weathered paint, but it's hard to tell in that image.