This is not exactly Wiremold, this is Plugmold and it has a copper grounding conductor.
You can get any fitting you want for this. http://www.wiremold.com/shared_content/pdf/ed1025.pdf
I agree that Wiremold 200, 500, 700 etc. is a questionable grounding conductor. I have not used those sizes in a long time but they do have their use and I would pull a grounding conductor.
We presently install a lot of G3000 or G4000 wiremold. This is big stuff that holds full size devices and can have a partition installed to separate power and data.
It is often specified in computer rooms, labs etc around the perimeter walls.