I finally did a couple pistol builds a while back and have two SBA3's. Each came with a receiver extension. On SB's website, they list an RE for $30 that is said to be milspec and 7075 and that's about it. I would assume it's the same thing that was included with the braces, but who knows? The price makes me question how good these are. Anyone know who makes them? Are they good to go, or should they be replaced by a known quantity (Colt, BCM, etc, etc.)? Leaning toward replacing them myself. Any thoughts?