I deleted a response I had written earlier supporting the idea this mule is not an LS, but a next generation ES. But, then I took the time to make a careful comparison between pictures of the current LS taken from the identical angles of focus we have in the three pictures of the mule. Everything seems to match ... down to the shape of the rearview mirrors. The C-pillar on the mule is camouflaged to actually mimic the C-pillar of the new LS. But this is just camouflage as is the heightened shape of what appears to be a rear spoiler.
Carmaker1 has told us we can expect the next generation ES to begin production in August 2018 with an October 2018 launch at dealerships. So I would think we should begin to see ES mules about now. However, I don't believe this is one.