The problem with folding stocks on the WK180 is; by the time you get to the actual folding mechanism, from the grip, its already a 5" length of pull (give or take an inch).
If you look at the photo of the WK180 folded in photo 3, there is about 6" of overhang from the pistol grip. Conversely, an AK would fold just behind the grip, or in the case of the top folder, even directly in line with the grip.
The original AR-18 had a folder but it didn't need an adapter and was built into the steel receiver.
Its hard to make a good folder for this design and I'm glad dealers have offerings.