To be fair, there aren't many 50s songs available, so every single one sticks out. If a song is labeled as 50s in the store and on this site, it should be safe to assume it will sort to 50s in the game as well. You shouldn't have to do research to know whether something is what it says it is.
That said, it's just $2. I'm sure you've wasted more money on worse things.