The earlier Erfurts did not have the receiver notch, including the early 1914 pieces. But late in 1914 the notch was added with the start of LP08 production and remained for the duration of production. Any Erfurts after that date without a notch almost certainly were reworks of earlier pieces or made up from earlier parts taken out of storage and placed into service.

Erfurt made Artilleries in 1914 only, but they evidently had a lot of surplus notched receivers which they used up later in the war. Here's a 1916 Erfurt with no notch. Regards, Norm

And here's another. Sorry for the poor photo, I sold this gun years ago. Regards, Norm

And the learning never stops here at Luger U...
dju

I have a solution! The poster could get with me so that we could swap barrels! I have a 1917 DWM with a 4" bbl and a notch in the barrel extension. Aside from the numbers' not matching (my 4" bbl. was numbered to the pistol with a different font by the arsenal or re-worker) we would each wind up with a proper configuration!

:) bam! you can use gunbroker to trade, I just found this all matching all original dwm commercial there.
The kicker is it has two matching mags!!! Buy Now :)

Glad you preceeded your post with a smiley face indicating a joke...as this Gunbroker offering is a joke.