Thanks Frank for your valuable input. I have not been fortunate so see many "K" variants, but I will keep my eyes open. I was postulating that the stocklug hole and the hump always existed together possibly indicating they both were integral in the manufacturing process, but I guess this is only a WAG! Obviously needs much more data to support. To muddy the waters further, my "41" commercial Mauser banner, has strawed parts AND the hump.