oil flaking is used for deeper oil pockets.
the oil pockets trap oil and use the oil as a bearing surface to reduce wear.
this process works off of the hydraulic principle that a liquid can't be compressed, it becomes a bearing surface.
oil is not likely to be put on this surface plate, nor will it be likely that the base will be incorporated into another machine.
my thought is that the flaking is purely decorative, and it's not serving it's intended purpose of trapping oil.
another purpose ,i suppose, is to look really cool-
that they nailed!