More inconclusive information ....
This is as frustrating to me as it is to you, but here is some more "discovered" information that could pertain to the C7 or the C8. The current C7 Stingray internal model code starts with "1YY." The following internal code numbers have been "discovered:"
Coupe = 1YC07
Vert... = 1YC67
On the surface, one would guess that these are for the C8. However, the other C7 model codes are:
Stingray Cpe = 1YY07
Stingray vert = 1YY67
Grand Sport. = 1YW
Z06 ............ = 1YZ
ZR1............. = 1YV
The new 1YC codes could be a new C7 model for a final 2020 model year or (probably) the codes for the C8 coupe and vert.
Nothing conclusive. Possibly indicative that there WILL be a Spyder/Vert offered for the C8. BTW, If they are testing a vert...and of course they are if one will be offered...it would help explain some of the spy pics showing rooflines oddly different from the vast majority of the other sy pic rooflines.