They must make two variations on the slotted and dimpled rotors. The numbers you quoted had an "s" suffix but the gold passivated ones appear to have a "g" suffix
I am assuming that maybe the "s" variation is a standard finish (i.e naked) whereas the "g" model has a gold coating on top of silver. Can you possibly verify that with the rep and get prices on both please
Note : the 324mm rotors for the gtr32vspec & gtr33/34 are 30mm thick not 32
The following paragraph was copied from the RDA web page :-
Grooved Sports Rotors
NEW! Gold Passivated, Directionally Grooved Disc Brake Rotors, For the Discerning Motorist.
These discs are ZINC PLATED and GOLD PASSIVATED to avoid corrosion, and have all the advantages of our standard slotted rotors as described below. They are packaged as a pair in a high quality gloss black box, and each rotor is marked as LEFT or RIGHT for easy identification and fitment.