I've had a 180 series for a few years now (180-06*** actually). But for one, it doesn't have the wooden top cover, but what seems to be a 181 series poly cover. In addition to this, it has the threaded flash hider and the recessed front sight/bayonet lug. I've spent a life's eternity milling another ejector and a few other parts for it, and refinished and re-blued a few of the parts. My assumption, though, ignoring the 181 cover, is that this is some sort of GB/180 series mix that someone threw together. Am i right with that or did ruger actually manufacture this kind of setup back in the day?