Yes, FILLERS is a Scrabble word!

Letter values in Scrabble US: F 4, I 1, L 1, L 1, E 1, R 1, S 1.

Is it a valid word?

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

used for filling cracks or holes in a surface
100 filler equal 1 forint in Hungary
copy to fill space between more important articles in the layout of a magazine or newspaper
anything added to fill out a whole
the tobacco used to form the core of a cigar