I think it's just a glitch, seeing how those who are level 41+ gets that quest listed twice for some reason.
I've heard that once you level up to 41, you will be forced to repeat all 7 quests for that level bracket, but you will be able to trade the dolls once you finish. I don't think it was meant to be that way, but it's what we have, I guess.
I got a level 40 character with a bunch of dolls saved up. Once I get him to 41, I'm gonna trade it in for a couple of chairs. ^_^