LR 5 and CR 18.104.22.168 in CS 6: Automatic recognition of lensprofile fails for Tamron 24-70 mm F/2.8 Di VC USD (A007) but manual selection is available an lenscorrection works. This issue occurs also during import.
This is expected behavior. You can set your own custom default by manually selecting the correct profile and then choosing "Set New Lens Profile Default" from the Setup popup menu. This will make the automatic selection work in the future for new images.
(For non-OEM lenses the automatic recognition is often ambiguous. This is why we do not always select profiles automatically by default.)