In Europe, most kosher products don’t have any symbols. We use the lists provided by whichever beis din we rely on. In the UK there is the KLBD, in the Netherlands the NIK, in Germany the ORD, in Switzerland the IGB and IRGZ… And more, and more. I check them all on my phone whenever I need to check something (so I often spend hours shopping…).
I don’t know how it is in the US, but don’t similar lists exist there as well? Maybe the girl was relying on such a ‘kashrut list’ from some beis din somewhere that does include that particular type of chocolate?