They are the same rotors as the 1098/1199/1299 era bikes and are 330 mm diameter. They are on an offset. No spacers are needed with standard rims.
You are correct I was referring to the caliper spacers if the OP wanted to purchase 320mm rotors instead of the stock 330mm ones.
are the V4 rotors any different from the 1199/1299?
yep, i found that out when i test fitted my stock rotor off my 959. whats the disadvantage running a 320mm oppose to the 330mm?