It's a problem.
On paper, we've got 4 guys who average at least 10 boards per 36 min (Dedmon, Holmes, Bags and Giles).
Obviously it hurts to have two of those guys not playing and a 3rd (Dedmon) playing like Ded Mon Walking..
Barnes has never been a strong rebounder.
If I'm scouting the Kings, this is one of their weaknesses for sure.