I owned some Lewyt built GRC-9 and i never detected the least quality difference among the various manufactures. Some knob varaiations and that was all. Of course - these were not produced under wartime conditions. "Wartime exigency" would be the term.

I recall 2 manufactures of the German WW2 receiver 'Torn.E.b' .

A knob from one would not fit the same control on the other receiver. The control shafts were of different diameter. I was astonished. So much for the "Gleichschaltung' intention, i suppose.

-Hue Miller