Good catch rrod436! Definitely part of some GM experiementing.
However, not only did we hear at the LA, ZR1 reveal, but since at several other major Corvette events (every time by top GM and/or Corvette team members), that the ZR1 is the very last bit of development work that we are putting into the C7, but also heard confirming statements to that effect from two internal sources that all C7 model development is over, so my guess is that GM is testing some part of some system and/or some component durability, and/or for some subseqent ME applicability.
Or is GM trying to rub it in to the Viper ACR, the Ford GT or similar, by besting one of their track records, i.e., that we do not even need our ZR1 King to beat you on the track?
Whatever's going on, I like it! A track focused "RS" Corvette would be an interesting move, particularly a non-ZR1. Regardless, I've often wondered why GM didn't offer a Corvette with "added lightness" in the way of manual adjust seats, mirrors, steering wheel, etc. You could probably save an easy 100lbs by dumping all of the power accessories and wiring.
This car doesn't even appear to have a speaker in the trunk. The placement of the tow hooks tells me two things; there is no place to store them, and they are making a statement. This is classic General Motors late phase camouflage: conspicuously inconspicuous.
The car is also wearing the Z51/Grand Sport hood, and not the Z06 hood, in spite of the Z06 fender vents being present, sans badge. The splitter is tapped for spats, which are not present.
In summary, my bet is that we're looking at the ultimate, track-focused naturally aspirated C7.
The ZR-1 rear wing isn't a simple bolt on to any other Corvette, so that also lends credence to this being an internal project. That doesn't mean it's ever going to see the streets as a production car. Perhaps a limited run of GS track-only cars. Or even a one-off car to be raced by someone at GM.
There was always a desire among some members of the Corvette team to do a Z06-X, e.g., a purely track version of the Z06 with lots of weight removed from it. Maybe some engineers decided to give it a go as a test bed vehicle.