Yes, OAKUMS is a Scrabble word!

Letter values in Scrabble US: O 1, A 1, K 5, U 1, M 3, S 1.

Is it a valid word?

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

loose hemp or jute fiber obtained by unravelling old ropes; when impregnated with tar it was used to caulk seams and pack joints in wooden ships