When apple replaces the phone you get the old sim tray?

[ouimetnick]

My brother got his iPhone 3G swapped back in January due to a bad speaker.
They gave him a replacement iPhone, but put the old sim tray with sim in it. So the sim tray has the serial number of his old iPhone and not matching the one of the replacement.
When Apple sent me an advance replacement 3G, It came with a sim card tray matching the serial number of the phone.
Did the guy at the Apple Store mess up, or is it supost to be like that?

 

[Pattycerts]

Old SIM CARD, new SIM TRAY.

Also don't think it matters one iota, unless you're friend is real nitpicky like that.