"Gibson's greatest success in the electric bass market came in 1963 with the introduction of the Thunderbird."
Uhum, which is why they deleted both the Rev and the Non Rev after a few years.
There are more TBirds around being played today (both old and new) than ever in the history of mankind. To be fair: Gibson has a track record of being ahead of the market with its models first time around and finding success only upon rerelease, see Les Paul, Flying V and Explorer guitars.