This is better asked in the Bridge forum, in case I'm missing some subtleties: <http://www.adobeforums.com/webx/.3bba3d54/>
The Filter list is self building based on the files. 'Model' filter shows up for me when I visit C:\Program Files\Adobe\Adobe Photoshop CS4\Samples\Photomerge
Do your files have EXIF data which includes the Model?