I don't think this does it. The expanded EXIF in my Aperture system shows focal length, max and min focal length (providing the camera fills this is). It does not show the lens used.
However, when I look at one of my photo's exif in iView, and under applescript, I can read the lens exif (i.e. 24-105 mm). The method you desribe does not produce this result in Aperture.
For example, if I shot a picture with a 24mm prime or my 24-105 mm zoom at 24mm, the focal length would both display 24mm and I would not be able to ascertain what lens it was shot with.
To my knowledge, Aperture does not provide access to this information.
I'd like to know this too, if I am wrong. Otherwise, I need to import with iView, then run scripts that dig this information out of the EXIF, and put it in the keywords, sync the annotations back to the master file. Then I open the file with Aperture, import it.
Please correct me if I am wrong.
J.
Various Apple Stuff Mac OS X (10.4.8)