Wedding Favors: My question is how early is too early?

My Wedding is 29 days away (August 1st, 2009), My question is about our party favors. I bought my favors from party city, they are these cute mini boxes with bows on them and we'd like to fill them with hershey kisses. My question is how early is too early? I'd like to put the boxes together and fill them with kisses as early as this weekend. I want to do it now so that I may check it off my list of things to do as I AM my own wedding planner and it would take much stress of me. I would just keep them safe out on my table until the wedding, as I am worried if I put them in the freezer or fridge in their boxes it may ruin the boxes when I take them out.