The original Thunderbird bass first appeared in 1963. Gibson never made it as a production left handed model until 2013, and only for that year. I believe they may have made one-offs here and there since the change of management in 2017.
In the earlier years I received many requests from lefty bassists from all around the world to make this guitar in left hand. At the time it was a much more expensive instrument to make than most of the other Gaskell models and it took some effort to build it to the intended sub-$1000 price point of the Legacy Gaskell range. Eventually I released the Gaskell Thunderbird-style T-BASS in 2012. It was a one-year only model as shortly thereafter we switched to becoming 100% custom shop.
Having come back to making guitars in 2023, I had a look to see if there were any lefty Thunderbird basses being made by anyone and I saw that there are not. So I have decided to re introduce the Gaskell T-BASS in 2023 as part of the "Hybrid Series." This means this bass is customizable. It is not made at the same factory that I used to used for the Legacy models and costs are much higher.
If you are interested in a left-handed Thunderbird-style bass guitar then the Gaskell T-BASS may be the one for you! However, bear in mind that Gibson Guitars are taking a very aggressive path to ruining other guitar brands that make guitars similar to theirs. They succeeded with Dean Guitars in 2022 and they are continuing to "come after" the boutique builders. This bass is not a bass you should think too long about buying. Do it now. While you can.
As always, all Gaskell guitars and basses are available world wide.