So I decide to look at how date metadata changes are made in Aperture. Which is when I realize I can't edit the date field. So I try the help file, but Aperture doesn't have a proper Apple help file. It only has a PDF. Nothing there.
So I google. I find this comment in an O'Reilly blog about what's missing from 1.1:
MacDevCenter.com -- Aperture 1.1--Apple ListensOooookaaay. So Aperture can't edit date metadata. Wow. Speechless I am.
5. The ability to change date metadata. Our office uses many scanned images and the dates used in Aperture are the dates of the scans, we want to change them to the date of the image was actually taken.
Apple, wake me up when Aperture can edit date metadata. More interestingly, where are all the computer reviewers? This should have been item one in Aperture reviews.
PS. The kb on this MacBook is awful. I hope it's an old store model they didn't replace. Apple, please send help to your Mall of America store ...
Update: There is a peculiar way to revise the date of an image in Aperture. Export to iPhoto. Change the date in iPhoto. Import to Aperture. Aperture respects iPhoto's date metadata!