Well any WOK is desirable, a problem free one all the more. By observations, 1916 is more common than 1917, but by "known" serial range 1917 is most common. If it were an "o" block it would be a huge jump for WOK/1916, as they are not known anywhere near that high. WOK/1917 are known into the "o" block but just barely (actually just "reported” as high as the "o" block, several "n" blocks are documented though, so the early "o" block report is probably good for 1917.)
WOK was a cooperative arrangement between private enterprise and the state, typical of governments then and now, they stole their part of the "deal" and formed WOK with machinery from occupied FN. Which ironically was owned by DWM at the time... FN was occupied and dismantled, machines going to start up WOK and to Spandau to enlarge their MG production.
DWM became involved at an early stage, buying up most of the stock on the open market, and by 1918 was able to buy the controlling interest in the company. Unfortunately, what seemed like a good idea in early 1918 turned out to a bad move by 1919, not only did DWM lose what remained of FN in Belgium (they owned FN prior to WWI), they also had to return all the looted machines that now made up Oberspree. To top it off, the Belgians canceled their stock and ownership of FN, so DWM lost FN entirely, the machinery at Oberspree and essentially the entire investment in the Oberspree Company.
I suppose they kept the land and building... I guess it hardly mattered though; the loss of FN was probably the gloomiest part, as it would have been an outlet for their patent holdings and a way to keep in small arms. Oberspree would have been a loss irregardless of the machinery, it was a rifle factory and DWM didn't need a rifle factory in 1919, they had enormous capacity already (MO & DWM combined could compete with all the arsenals combined - through efficiency, which is always lacking at government firms, - why WOK had such a bad start up, the government was involved.) and small arms production was no longer an industry of promise in post Versailles Germany.