Hey,
That is correct 🙂 , more like USB socket that is supposed to be waterproof and connections going direct to battery , if it has an On/Off switch, that’s good . Dont test it on critical parts (like a phone!) , find an old power bank, see if the bank charges up well. Then try some kind of usb device from home like a keyboard, fan etc… just to make sure they work as intended when bike runs also.
Just incase it isnt damaged by previous owner or there is some kind of “overspike” of current (after all, your bike looks like it needs a new stator and charging system overhaul? ) – I would not know if he plugged something to the USB socket that annoyed the charging system of the bike.
// Meditation doesn't mean you have to sit still....