Opened up a USB stick and it looks a bit odd

It's possible for it to be good. I have micro size USB flash drives where everything is inside the silver connector portion. The ribbon would only be for the LED.

This is what it actually looks like.

We managed to get a hold of another USB stick (same type, same brand - owned by somebody else). Opened it up and it looked the exact same as the one shown in the pictures above.

Well the pictures aren't 100% clear but it could be that all the electronics fit inside the USB plug.

If the drive works ok in your computer this is the case.

If you are adventurous you could try to open the metal casing of the USB plug. Warning this could destroy your drive (so backup data first).

One would actually have to check both halves of the caseing, but just from looking at the picture this half of the case does not appear to be designed to hold more than it currently does.

As such it at least appears unlikely that something has been taken out.

If the person had their work on it it is probably a real USB.