Don thanks for your update and relating the experience of seeing a period used on other tools as well. I am relatively inexperienced with these tools and just found it an interesting point that the HK tool had a period. I remember reading about your custom firing pin gauges in other posts. If anyone is interested in the one I found, just go to the Canadian Militaria site, germanmilitaria.com and look under new items, or try this:
www.germanmilitaria.com/Heer/photos/H036881.html