Just did this mission on 1/20/06 and the pelts dropped off every panda. We got the Clapsed Chain Arms but was hoping for the mask. There is no timer after winning this mission.
We parked everyone at the gate all being Mages and had a Ranger go out and pull the Spiritlings and Pandas. Got a few tigers and gorillas but all went down quickly as the mages mowed over everything.
We then park all the pets in the fort at the cave entrance. Turn in pelts and the boss pops on the pets. Pet kill very quickly and we all watch. Seems to give a ton of AA exp at level 70. Seems like 2 AAs.