I have a prewar CZJ Sonnar 50mm f1.5 that was coated after the war (looks like original Zeiss but Iīm not sure). The lens is from a Contax IIIa and I use it on my M9 via a Jupiter 3 focusing helicoid.
The coatings are really good and flare is well controlled. Wide open there is always a hint of flare/coma/astigamtism and very low contrast, stopped down to 2.0 or 2.8 contrast ramps up and it delivers clear snappy shots, really impressive for such an old lens.
pictures with the lens: