Chevy Corvette C8 TEST CARS Spotted in Colorado! E-Ray? ZR1?

Hey everybody! I found these 4 Corvette C8 test cars that recently arrived in Colorado presumably for high altitude testing. Interestingly, one was a non camo'd obvious C8 Z06. Another looked like a Camo'd Z06, and the other two looked like they may have been E-Rays. E-Rays would make sense to be testing, but the Z06 has already been delivered to customers, so why would they need to do testing now? Maybe using the platform for the ZR1? What do you guys think?