I will Bite:
From a Marketing point of view, the 396 was competition (?) <Timing??> to the introduced Mustang 390 (GT/GTA), unfortunately I bet the Stang BB cars smoked the Camaro as far as quantities. The Vintage ads seem to promote the Super Sports in general in 1968, there is a great variety and often the internal Big Brther was included (Vette).
OK Post up your 68 Ads I have a BUNCH hanging in the Garage being a 68 Guy at Heart.