Will Lightroom 2 recognize adjustments to photos made in earlier versions of Adobe Camera Raw?
Raw files edited by previous versions of Camera Raw will maintain their previous appearance when imported to Lightroom. For Lightroom to respect the previous edit, those files must have been edited with the preference set to save image settings in sidecar XMP files. Files edited in Camera Raw after being imported to Lightroom can be updated in Lightroom by choosing Metadata > Read Metadata From Files. Note that this menu option is only available from the Library.