DWM started putting the hold-open on the P.08 in 1913, but some of the 1914 dated P.08 pistols don't have the feature. The stock lug was also added in 1913, but in 1914 some of the pistols still didn't have it. Your 1914 still has the old style sear bar, which would have been altered if it had gone back to have the hold-open added.

A nice find as the earlier P.08 was made in more limited numbers, and attrition accounted for a number of the earlier pistols.