I have a slightly different but related problem: After moving to 10.7.4, my iPhoto program appeared to be recognizing my Pentax K20D photos and Panasonic DMC LX5 photos as RAW (i.e., it labeled them as "RAW" in editing mode), but when I edited the photos, iPhoto rewrote them as much smaller files. I did not notice the problem for a while because the newer iPhoto software doesn't allow viewing of file size information in "edit" mode. When I noticed the problem and tried to revert to an original photo, iPhoto gave me a giant exclamation point rather than a photo. I tried viewing the original file in my finder and discovered that iPhoto had modified it from 11.4 MB to less than 3 MB (or at least, that's what the finder says). After reverting to previous RAW updates and repairing permissions, my unedited photos are now tagged correctly as RAW, but hundreds of the photos I've edited (and, in some cases, even the photos I've only glanced at in "edit" mode) are tagged as JPEGs, and iPhoto won't let me go back to any previous versions; as near as I can tell, any previous versions have been overwritten. Ordinarily, I'd be able to use time machine, but since it's field season (some insects are around for only a week or two, and some amphibians migrate or only emerge at certain temperatures and humidities) I edited the photos as soon as I pulled them off my camera so that I wouldn't fall behind. My time machine has the same corrupted versions.
I've tried reverting to the previous RAW update, downloading the 3.12 update, & repairing permissions. I've tried opening the damaged files in Aperture. No luck. Next step: removing Lion and going back to 10.6.8. Any other suggestions would be welcome.