Yes, but 1978 isn't early for the Odyssey brand. Magnavox's original Odyssey and its dedicated Odyssey system line from like 75-77 were all pretty strong sellers for the size of the tv game industry at the time, and even going through materials and newspapers from the early 80s, the Odyssey2 does get mentioned about as much as any other non-Atari competitor. Atari just blew up in 1980 on the strength of Space Invaders and dominated the discourse, but the Odyssey brand was still pretty notable.
We never knew why it was called Odyssey2. Never knew about the earlier models.