There is a Color TV-Game commercial supposedly from 1977 (not totally clear whether this is the year of the ad itself or the year of the product launch) [1].

[1] https://www.youtube.com/watch?v=1VmwNej8noQ

I think a good argument can be made for 1977 or 1978

https://en.m.wikipedia.org/wiki/Color_TV-Game

They came out with a 3rd machine in June of 1978.

The commercial features the first two machines. There's many plausible reasons for this including, most prominently, that the third might not have been released yet.

Certainly not definitive but likely