If your chainrings only have 500 k on em, and it's your middle ring, chances are they're supposed to be like that. Most companies have different tooth profiles and ramps or pins on the sides to help improve shifting. Does the chain ring look like it's been ground down in one area? If you closely at newer bikes you will see the same pattern.
Did you grind on some concrete or just normal riding? If you don't remember any significant hits, chances are your chainrings are fine!
L8R
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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
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