ID: Danish Sideboard
Nicely made piece. Solid teak apron. LumberCore (møbelplade) carcass, not particle board, dovetailed to the bottom. Probably from the late 50s or early 60s. Based on the construction I would say it skews earlier rather than later.
Since the designer is not given the John Stuart catalog, that very strongly suggested it is not one of the most famous designers. But that rules out only perhaps 3-4 names.
Since John Stuart was the sole distributor in the USA based on the mark, and the company seems not to have marked their pieces themselves, then you are probably not going to find a marked one in the USA by searching in English. I would suggest trying to find another in Denmark by searching in Danish.
The only other thing that comes to mind, which I think is very likely meaningless, is that the waist between the legs and case is a detail I've seen on the Dux Florida series, but they are Swedish. (There is a name for that waist in Chinese furniture, where it is very prevalent, can't remember the name right now). It is interesting how it makes the piece look not very Danish in style.
And more photos are always good. The sides of the drawers, hardware, etc, etc. Sometimes it is the little things.
Being from Europe, I know next to nothing about John Stuart. The only thing I know is that they distributed France & Son and Søborg (and probably many others).
France & Son was not a part of the DFC club but Søborg was. Plus I own a Søborg nightstand with a round textile DFC sticker (I haven't seen the DFC textile stickers too often).
Here you are: http://www.ebay.com/itm/Pair-Mid-Century-Teak-Cabinets-W-Tambour-Doors-b...
I haven't seen your piece in Søborg catalogs available online but maybe I looked too quickly... The list of designers that worked for Søborg is rather limited and if it is a in-house design it can be attributed to Arne Jacobsen 😉
Lauritz believes it is Søborg as well. I am guessing because it is marked. This seems like too strong a coincidence, even though Lauritz is very unreliable: