I only have Deathwing left, when I go to my raid into for the lockout. The group I was in killed Deathwing and when I enter it says if I want to accept an 8/8 lockout.
Does this mean I can join another persons DS raid that is on Deathwing or do I have to wait until ext week?
You can enter a non-heroic lockout at the boss listed as "available" on your lockout. You cannot cross heroic lockouts ever, so if he's dead in your heroic lockout, you missed out on the chance to kill him on heroic this week. And if you zoned in and accepted the 8/8 lockout, you may be saved to all 8 even on normal.