I'm seeing the same thing. I just ran exiftool on a RAW file and see this:
ExifTool Version Number : 9.12
Lens ID : Summicron-M 35mm f/2 ASPH.
Red Balance : 0.583497
Scale Factor To 35 mm Equivalent: 1.0
Shutter Speed : 1/16
Circle Of Confusion : 0.030 mm
Field Of View : 54.4 deg
Focal Length : 35.0 mm (35 mm equivalent: 35.0 mm)
I don't really know the EXIF spec so I don't know whether "Lens ID" is the standard field that should be used.