I consulted my Japanese GT-R book and from what I can gather, there are no definitive answers, only because it was offered as a normal model, like a V-Spec II.
I can tell you there were 3 M-Specs built as test models in January '01 (BNR-400801-803), before they were officially released in April '01 (BNR-401356 onwards). The EY0 gold paint came the Japanese Primera.