Responding to the question, I do not have a reference or basis that indicates that these HSc's were for testing. As with other longstanding HSc collectors, I assumed that the designation of “Army test proof”, as detailed in your book, Axis Pistols, (p. 36-37, and of “military test proof” in Pender’s Mauser Pocket Pistols, p. 216, indicated that you and Pender must have had some good documentation that these pistols were, in fact, being tested by the German Army.
One really could question the significance of the small eagle on the left rear tang and whether it signified anything at all, other than merely a continuation of its use as on previous Army procured M1934’s. Perhaps the Heereswaffenamt simply directed that the Army take on the new Mauser HSc and production continued utilizing the previous proofs and acceptance stamps.
In tracking the earlier HSc pistols with the smaller E/655 and the “Army test proof”, identical to that used on the Mauser 1934, a number of pistols bearing the “test proof” have the larger E/655 Army acceptance stamp. AutoMag, 01/02, reported serial 714527 as having the “test proof” and large E/655. Serial 715099 was reported in AutoMag 07/98 as having the same markings. It would appear that the transition between Army Variety I and II was not that clear cut...with examples of both E/655 acceptance stamps being observed.
Uncheckered grips, in my humble opinion, were not on the mentioned pistol when leaving the factory.
I would be very grateful for any input on this subject.