Seems like most of the ones I have seen are TST55L or TST60L. Essentially a TST50 + 5,000 yen for lefty + 5,000 if it is a premium or custom color.
1987 catalog
"TST55L & TTE55L * Left-handed versions of TST50 & TTE50 - all specifications as per R/H models."
https://vintagejapanguitars.com/tokai-1987-catalogue/
1987 catalog
"TST55L & TTE55L * Left-handed versions of TST50 & TTE50 - all specifications as per R/H models."
https://vintagejapanguitars.com/tokai-1987-catalogue/