Maybe this ten years old thread will be of interest.
http://www.vikingsword.com/vb/showth...de+katar+stamp
A second thought. I dont own any of these blades myself, but I have seen the katar mark on three or four blades, one even with an additional trisula, and all of these stamps were very deep. This must mean that the stamps were made while the blades were hot, as I dont think such a deep stanp could be made on a cold blade.