I saw my first MO501 batch this week at my local Walmart, and as everyone else has reported, it's green.
We've had M05 stuff here for a while now, but oddly enough we got MO502 and newer stuff first, and the M0501 stuff didn't show up until later. I also saw some M0522 stuff too.
I've still got 75L of the green stuff, and my dad needs some for his upcoming oil change, but I'm going to switch him over to gold GC so I can preserve my green stash for my two cars and my mom's car.