When you throw the quest item into yogg's mouth when he does Deafening Roar a party loot item will be available for those that have the quest. A Reforged Val'anyr will be the quest item you loot off yogg that's looted like the item for the daily heroic is. After you acquire the Reforged Val'anyr you take it back to the Archivum Console and complete the quest. Therefore, multiple people can craft their Maces in the same raid.
Here is the Reforged Val'anyr that you get off yogg:
http://www.wowhead.com/?item=45897And here is a daily heroic item:
http://www.wowhead.com/?item=43823They're both party loot items which means they act the same way in terms of looting.