I have a NOS cover that is painted.
I have another that does not appear to have been painted.
If you look up front by the oil slinger cover, there is an oil passage bump in the case, it is on theneeds under side. Hold cover with kicker on left, look at it from the bottom. The bulge for the oil passage, does the outer end appear rounded, or run toward back of the case, at about a 40 degree angle.
If its angled, then I conclude that the one I have is factory painted.