You are correct, a new book arrived yesterday with a better picture:Seems to be a Daimler K-Flak (Kraftwagenflak) with Krupp 7.7cm L/27 M1914 or a truck-mounted 7.7cm Rheinmetall Flak gun.
Here are some other examples:
Daimler K-Flak (Kraftwagenflak) with Krupp 7.7cm L/27 M1914 (Foto source from: https://landships.activeboard.com/t63605220/kraftwagengeschtz/?page=1#comment-63605358):
View attachment 16902
Truck-mounted 7.7cm Rheinmetall Flak gun (source from drakegoodman on flickr.com):
I posted one yesterday with a picture of the AA gun on a flatbed truck from a new book that arrived yesterday. I will scan it and post it againI can still see the photo you posted on August 28 th.