Been spending a lot of money on period correct parts for a Colt 601. Brownells sells lower receivers, but the color is not quite the XM/Colt grey. The upper receiver purchased last year is black. Wasn’t really thinking about it at the time. Grey is out of stock. The dimpled controls are period correct reproductions. The colors, other than the magazine release button, are correct. I’ve got a tool for the flash hider on order. Once I get it, I’ll switch out the birdcage to a duckbill. Called a metal refinisher about 90 miles away who will re-anodize the aluminum parts with a reasonably close color match for about $100.