Rolex Explorer II on Ebay

[Spunga]

If your really that concerned, get a timed receipt on delivery, take it straight to Rolex and get a timed receipt from them to prove you had no time to change/modify the watch.

Rolex will prove its authenticity before seeking your authority to service or pressure test it. If its fake they will hand it back. If they don't, say because its real but stolen for example, you should have enough proof for any claim.

Leave the window of opportunity open to long between receiving and making any statement about its authenticity will cause you problems later.

BTW, box and papers can mean anything. It may come in a BOX, and the paper could be say a docket/receipt from some back alley watch repairer. Unless you check exactly what it means you should expect to get exactly what is described, which may or may not be what you expected.