Yes, but you had a few chances to get out of the bottom.

You had to be a "C-player" for something like three consecutive review periods before you were let go.

(source: my father was a manager at GE for decades)

Do they still use stack ranking?

Does anyone know if they fired the bottom 10% of the C suite?

GE under Jack Welch essentially invented stack ranking and its attendant hardline firings.