As Mike has pointed out, these Triple-X Eagle proofed guns fall into two categories...the 5-digit commercial series that lacks a chamber date and the military style marking of the 4-digit "a" suffix series that is chamber dated 1914. The unusual thing about these limited variations is the 1908 pattern of most of the the guns in 1914, well after the stock lug was introduced. The Commerical 5-digit series might be designated "08/14 Commercial/Military" while the 4-digit "a" series might be designated "08/14 Military". The Commercial guns having a stock lug might be called "1914 Commercial/Military". At least, these are my designations
. All of the known 08/14 Militaries fall into the 8XXXa serial number range. It would appear that the 08/14 Commercial/Miliitaries and 1914 Commercial/Militaries were indeed diverted from Commercial stock, while the 08/14 Militaries were specifically produced for the Army using up existing 1908 frames on hand.
The very limited numbers and unusual configuration and proofs make these variations quite desirable as collector items. Unit marking is icing on the cake.