http://molotok.ru/show_item.php?item=5246284488
The knob looks crude, I think it is a non-factory modification.
This seller is in Nizhny Novgorod and does not send abroad.
A picture from the interior looks normal:

http://www.ussrphoto.com/UserContent/942015_b116a2b2f044.jpg
Changing subject - on Gomz Sport lenses:
Sovietcams.com lists a so called Technical Sport, PK0640 at:
http://www.sovietcams.com/index.php?-1465305895
or
http://www.ussrcameras.ru/?rp=1&action=tovar&tovar_category=26&id=75
This body has an externally completely different Industar-10 lens, made by Gomz.
Well, I found the same design but made by Komz (Kazan) and just ordered it. Images below. It has something in common with the Barbus-2" 2.5/28mm lens.
Any information available on this strange, so called "technical" lens?

http://www.ussrphoto.com/UserContent/942015_571272474.jpg

http://www.ussrphoto.com/UserContent/942015_571272558.jpg
travel-images.com





