Yes, DECKLE is a Scrabble word!

Letter values in Scrabble US: D 2, E 1, C 3, K 5, L 1, E 1.

Is it a valid word?

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

rough edge left by a deckle on handmade paper or produced artificially on machine-made paper
(paper making) a frame used to form paper pulp into sheets

Also: deckle edge.