I would use a 8x or 10x loupe and make sure there is no active corrosion in or around the pinholes. Once I made sure there's no active corrosion, I would lube it up (I like what Bullman said, "lubricant resevoirs") and enjoy it. The little pinholes are extremely small and in an area of the rail that I don't believe is subjected to any real stress. In fact, that area of the rail on a Springfield XD-45 pistol is plastic. It's my understanding that the area subjected to real stress is far forward the pinholes.

FWIW

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1st Signal Brigade, RVN '70