Lens corrections for Panasonic micro 4/3 lenses are in the lens firmware and written to the raw file. Lightroom reads and applies these corrections when it renders the raw file. You don't have any choice about this, and there are no Panasonic lens profiles included in the lens correction section of the develop module.
This is the case with every m4/3 lens (Oly, Sigma). However, using the Adobe lens profiling software and procedure, you can create and install into the correct location on your computer a lens profile that LR (or ACR) will apply on top of the default corrections encoded in the raw file (or baked into the JPEG). Since the Adobe profiling software takes into account the encoded correction parameters when it creates the custom lens profile you are not "double profiling" by selecting the custom profile in LR. Alternatively, you can download and install profiles others have created. (The 20mm f1.7 profile might be one of mine.)
Essentially, you are tweaking the manufacturer's parameters. If I recall correctly, Eric Chan has said on the relevant Adobe message board that the manufacturer's correction parameters tend to the conservative, so the automatic corrections may leave you slightly undercorrected.