For whatever it's worth, my preference for some type of stamping or other identification is to make the build knife "special" and identifiable as a build knife. That's a little less important I think with a BMK as opposed to an RMK since all BMK's are different so maybe a COA is fine but I still like the idea of "something" to indicate that it's a build knife. Even if it's just a special emblem of some type. And if it creates confusion years down the road well that'll give our kids something to debate on the forum the way we debate the many Randall mysteries that are out there. But, like I said earlier, it's not a huge big deal to me so whatever folks want is great.