The star icon can appear 2 different ways, or not appear at all. Each version tells you something about your Fundraiser.
No star means there is no data on the fundraiser record and there is no label added.
The outlined star means that you have added a label, but have not collected any data on the fundraiser (i.e. the fundraiser has not completed a GivePanel form).
A gold star means that you have labeled the fundraiser AND collected the fundraisers data through a GivePanel form.
A gold star can also help you verify if your fundraisers are matched to their respective registration because when a fundraiser and registration match, the registration data is placed onto the fundraiser record automatically.