Point, Monsieur Kettler.
The distinction you make is a valid one. The 2cm Gebirgsflak 38, aka Geraet 239, was a lightweight version used by paras and mountain units. The weapon suffered an inherent design flaw, however, as its tubular tripod mount proved to be TOO light for the gun. Accuracy suffered as a result.
As for the book, you're welcome to borrow my copy which I clearly have yet to read in its entirety. Patience, my good man.