Rock n Roll silver tequila?

Hey, question. I got a bottle of Rock n Roll Platinum Tequila for my birthday recently and I just wanna know, the top is supposed to be a sort of flask, right? Or is there another use for it? I opened it and noticed the top had a little cap you could unscrew to get to the inside of the head of the guitar bottle, and i’m wondering if there’s some specific use for it or if its just an additional flask. Thanks for the help !