Well I have managed to install exiv2 in my windows machine an run it against some of the images take with the tamron.
I think the relevan info is the Canon makernote called LensType.
As expected it just shows 255
There are other fields that identify the lens model too
0x0016 CanonCs LensType Short 1 255
0x0095 Canon LensModel Ascii 74 TAMRON SP 70-200mm F/2.8 Di VC USD A009
0xa434 Photo LensModel Ascii 40 TAMRON SP 70-200mm F/2.8 Di VC USD A009
Now the only thing is needed is map that lens identifier to the lensfun lens database ID.
Under darktable lens correction module, the lens name reads
Tamron SP 70-200mm f/2.8 Di VC USD
I have checked other lenses and they are automatically detected, like the tokina 11-16 or the canon 17-55.
So there must exist some central database for the mapping.
I would like to contribute that info in order to correctly identify this lens under canon cameras in fore coming releases.