There really were two guys called TREBBE at the 7/78.
Bernhard TREBBE, lightly wounded 1914:
http://des.genealogy.net/search/show/228636
And Gerhard TREBBE, lightly wounded 1915:
http://des.genealogy.net/search/show/3207780
And two others TREBBE were at the 3 and 5/78.
Do you know how difficult and almost impossible it is to find a helmet exactly matching with a Überzug? (same unit, same Kompanie and same number of Garnitur.....). I would not hesitate to make a deal with the AK helmet to get the matching Überzug and of course some money for the difference of value from your friend. But this is only my two cents, I do not like WWII helmets....I do not know how much is the value of a AK helmet, but I perfectly know the value of a rare WWI matching set....
Philippe
:wink: