The word "Signature" on the serial number sticker and the 480 Joule meter reading indicate pretty conclusively that you have the real 600 watt version. Also, it is likely your serial number is preceded by the designation "SS." This is yet another reliable indicator.
Carver has been profligate in post sale autographing. He'll sign pretty much anything he designed, so his signature on the front has come to mean very little.
Telling the difference between 400W and 600W is pretty close to impossible, all else being equal. This is only about a 1.5db difference, after all.
All of Carver's Sunfire "Load Invariant" designs use fundamentally the same circuit, with more or fewer output devices. They all sound practically identical, which is to say they all sound terrific.
Carver has been profligate in post sale autographing. He'll sign pretty much anything he designed, so his signature on the front has come to mean very little.
Telling the difference between 400W and 600W is pretty close to impossible, all else being equal. This is only about a 1.5db difference, after all.
All of Carver's Sunfire "Load Invariant" designs use fundamentally the same circuit, with more or fewer output devices. They all sound practically identical, which is to say they all sound terrific.