My dealer told me all I needed was registration, vin, and id, and like $15.00 to get the key or maybe it was keys.
I myself would rather spend extra and get a complete set of factory keys, two regular, and one valet key. that way I'd have extras.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.