I have run lsusb -v
for my USB-connected GoPro Hero 4 Silver. The returned iSerial
indeed looks like a (unique) serial number. The returned number is composed of a single capital letter followed by 13 digits.
Unfortunately, I don’t have multiple GoPro cameras to confirm that they actually all return different numbers. I neither have a Sony AS-30 to check there.
EDITED to add: I have just found the same serial number returned by lsusb
on a sticker in the battery case of the camera. So it indeed seems to be a unique serial number.