Yes, FINALS is a Scrabble word!

Letter values in Scrabble US: F 4, I 1, N 1, A 1, L 1, S 1.

Is it a valid word?

FINALS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the final match between the winners of all previous matches in an elimination tournament
an examination administered at the end of an academic term

Also: final examination, final exam.