Not always. Sometimes a 'given' story can be inspired by real events but might have significant alterations or embellishments to make it more engaging or fit a certain genre.
It depends. Sometimes a story might claim to be based on real events but have some fictional elements added for entertainment or narrative purposes.
It's hard to say for sure. A story presented as true could have some parts that are accurate while others are fictionalized or exaggerated to make it more appealing to the audience.