What Toto Toilet is this?

One piece. Fill valve says Hunter. Porcelain says Toto 1.6 Gpf/ 6Lpf behind hinge.
Thanks.

Inside the tank you might see CST854S

That looks to be an older Ultramax. I had one just like that.

Hunter was bought out by Korky. Same valve, slightly different shape to the plastic case. The replacement valve would be a Korky MaxPerformance.
The red Korky 3" red flapper would work in place of the plastic lift flapper. You can still buy the rubber replacement dics for that older version still. It looks like the handle has been replaced. THU004

Thanks! No writing in the tank remains, but the pictures sure match.