They look like really nice rifles, nothing stands out that might be wrong with them, - that style of DC is common on Imperial rifles, they usually come out strong after repair. I had neither of these recorded, the Spandau is the most interesting, although I like Amberg very much, but the Spandau is quite late, the highest confirmed made by Spandau are k-blocks, though several reports have them to the m-n blocks, but i am pretty sure those are Danzig builds, but they are old datasheets (another is a Hermann Historica auction, which might as be a "report"), and without the acceptance pattern I can't be sure the maker. Spandau also has a very distinctive serial font and suffix, but again datasheets have limitations in that regard.
Really, of all the 1917 makers, Spandau is actually quite hard to find actually made by Spandau, - you can find Spandau/17's easy enough, but most seem to be made by others or interwar builds. The right receiver will also tell you, usually, who made the receiver, both Peiper and S&H made a lot of receivers for Spandau in 1917, most are one or the other, the acceptance tells you which. Pieper's are far less common, for whatever reason most were not used during the war, or at least among the rifles that survived.