Rusty handle bar under grip

[07 CVO Road King]

Last weekend I removed my handle stock bars for new bars to be placed this weekend.  When I removed the left grip the whole bar under the grip was very rusty.  Has anyone else seen this before on the left side only?  I'm thinking maybe sometime in the past the grip had been loose and worn the crome off.  But I never noticed it loose and I never remember tightning it.  Its really just out of curiosity that I ask, grips and bars will be new when put back together.  Oh the grips were OEM also.

Van

[Boss07Hog]

Just removed left grip on mine this past weekend and the same thing.  Haven't checked the right one yet though.  Think moisture must get trapped in there and steel will rust with moisture.  I didn't worry about it, not seen under grip.

[07 CVO Road King]

I think its odd that that is the side that hangs down lower when parked.  I kinda wonder if the clutch fluid (DOT 4 brake fluid) might leak slightly when parked and handle bars locked to that side.  Just a theory though.