Rohloff non-OEM hub in Rohloff OEM frame?

I have an oldish frame with horizontal dropouts, and I am considering
trying out a Rohloff hub for it. A non-OEM version is needed, one with
the lever going along the left chainstay.

Now, if I like the hub and decide to build a bike on a new frame,
it will be the frame with Rohloff-specific sliding dropouts. (I do
not want a chain tensioner, and horizontal dropouts are rarity
nowadays; also wheel removal is easier without the chainstay lever.)
Can the non-OEM hub be directly used in OEM dropouts?
If not, is the conversion as easy as changing some side plate?

Thanks in advance.

--
Konstantin Shemyak
My Nexus-7 tandem with kidback for riding with two kids:
http://konstantin.shemyak.com/cycling/Tandem