I'm not sure what brakes I have, but I think there are 2 pistons and that they might be sliding/floating or something like that.
Yes, lower spec and black.
The noise is coming from the calipers. I shook them and they are kind of slightly loose to either side and it seems like the pads move a bit in the rolling direction when I push the bike back and forth with the breaks applied.
In that case I'd say this is normal and don't worry too much about it.
Since these are brakes we're talking about, It's always worth being _completely_ confident in your brakes, so if you've got _any_ concerns about them it's my advice to take it to a dealer and voice your concerns and get _them_ to tell you "that's normal". (especially since you're still under warranty, they'll almost certainly do that for you for free).
big