[mothered]

surely it would look better to leave the tracking number there to make it look more authentic?

Exactly this ^

Tracking must be shown as delivered from consignor to consignee. Moreover, packages are scanned at the collection point, at the carrier's depot and when they reach their destination, hence the tracking details must remain Intact. If they're missing, many carriers will generate a new shipping label- DHL Is one of a few who tends to do It.