The .XMP sidecar file is created in PS ACR by making adjustments to the .CR2 file. If no adjustments are made, there is no .XMP file, which is why I couldn't upload a true 'before' version.
Here's my editing process.
Download CF card, through Finder.
View files in Photo Mechanic.
Select files to edit, hit Command E to edit in Photoshop's Camera Raw.
Click Done or Save in ACR.
Add Metadata (IPTC/Caption) info to files.
I will check my PM prefs dialogs.
Thanks,
Scott