At least one source thinks it will debut prior to the NAIAS, but
did NOT name their source or when or where it would debut. A New Vette Gen is obviously a big deal and one might justify labeling the C8 Debut as the biggest in Vette History (The Motorama debut was only of a concept. No production decision was made at the 1952 Motorama).
There is almost no doubt that the first C8 will be a 2020 model, but will it be a long ~18 month model year? Maybe. IMO, the C8 Debut will be at the January 2019 NAIAS and production will begin in early spring 2019. Deliveries? Who knows. If applying GM's past habits, they will stockpile C8s at BG until last minute computer control algorihms are finalized and loaded into "completed" inventoried cars. Because of the already lengthy gestation of the C8, it's possible those algorithms will be finished prior to the START of production in 2019 which could mean late Spring or early Summer deliveries. Excited?