Ed,
Perhaps to test hardness consistency throught the piece.
Howard,
Random parts testing. Nothing says its not a police "thing", one way or another.
Here's a picture posted by Thor of a property marked Erfurt (date hasn't survived the archive):
http://members.rennlist.com/lugerman/TDDErfurt3.jpg
In another post there is a comment about Thor's K-date with several of these dots.
Here you'll find another one, posted by Herb, look at "side stamp"--no indicatin what the gun is:
http://members14.clubphoto.com/herb5...43/guest.phtml
Here's a previous discussion on the topic:
http://forum.lugerforum.com/showthre...=hardness+test
Its true that most of the examples have more than one dot in close proximity.
Here is a picture of the breechblock of my Simson rework of a First Issue Military, it has a dot where one expects to find a firing proof:
Couldn't say what this all means, but it does seem to be a fairly extensive practice with no good explanation.
--Dwight