It was suspected this redeco would appear. Looks good.
I'm kind of surprised it actually has its own number (MP31) as opposed to a suffix on MP22 (MP22D). The numbering 'convention' since MP10 has been that figures with remoulded parts get new numbers (Sideswipe MP12/Red Alert MP14, Wheeljack MP20/Exhaust MP23), while recolours are given suffix letters (Sideswipe MP12/Tigertrack MP12T, Starscream MP11/Skywarp MP11SW/Thundercracker MP11T), although this has been thrown out somewhat by G2 Sideswipe (MP-12G), Soundblaster (MP13B) and Ramjet (MP11NR).
To my knowledge, MP Optimus Primal's number hasn't been confirmed yet (someone correct me if I'm wrong), but colour images surfaced in the last few days.