Yes, NECKS is a Scrabble word!

Letter values in Scrabble US: N 1, E 1, C 3, K 5, S 1.

Is it a valid word?

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

the part of an organism (human or animal) that connects the head to the rest of the body
a narrow elongated projecting strip of land
a cut of meat from the neck of an animal
a narrow part of an artifact that resembles a neck in position or form
an opening in a garment for the neck of the wearer; a part of the garment near the wearer's neck

Also: neck opening, make out.