I'm in the same situation as you, but with my ZL1 1LE, and today my dealer will once again ask to te GM area manager to do something. The last time he did it, my car changed status, but nothing since then. My dealer also suggested for me to call directly GM... like they are going to have answers...
Not a C8, but my ZL1 1LE has been sitting on the parking lot of the plant since March 24th. I just gave up on it now and may it sit in peace with the sun cooking the birds s**t on the paint.
Even more surprising, on C8 tracker, a small dealership in Quebec City (Marlin) who only has 2 C8 got one Z06 allocation. I guess there is really no sure way of knowing and predicting with those Z06 allocations...