Mark has a 5000 p block, same as this one, and it is the finest he had seen when he told me about it in 2005. He said then that he'd seen 5 Oberspree/18's and one Oberspree/19. Currently I have recorded 14 Oberspree/18's and 3 Oberspree/19's. Mark then said that Oberspree/18 and 19's were the toughest of the wartime makers, especailly to find nice, Imperial and matching. (Meaning not postwar assembles, which some are, as are some WOK/17's)
As you can tell by this rifle, and Mark's, Oberspree didn't rollover from 1917 to 1918, they continued where 1917 left off, which is the n-o block. All Imperials fall in to this pattern, some 1st blocks also exist, but are postwar or extremely late wartime finished after the war. The one in M&B VI is such a rifle, it has postwar features, most notably the FP on the barrel next to the serial, which no n-r block has, - but all the Oberspree/19's do...
Anyway, show the right receiver of this Oberspree/18? Also the stock acceptance if you have the time?