i guess you better DM the manager for this.. i backed read the rules, it says nothing about your concern.. this is only what i got :
"Help us spread the word on FundYourselfNow and you will receive a stake every week! All you need to do is add our official signatures & avatar to your Bitcointalk profile. We will randomly check all our Signature & Avatar bounty participants once a week, to ensure long-time supporters receive an increased stake.
You need to make at least 10 posts a week in order for bounties to count."
no other infos about leaving the campaign before the ico ends and will still get some stakes. just wait a bit, maybe the manager will answer your concern.
I've already sent them a PM twice and they don't respond.