I was made aware of the potential to swap out the valve springs on my 2002 Z06 I recently acquired. I bought an endoscope and went down in the oil fill to see what I would find. The spring I could see had some yellow on it, but was mostly grey. Is this something I should be concerned with and replace or are these OK? I also understand there may be info on what serial numbers are involved and if someone can point me there, that might be a huge help. Photos are below of what I saw with the endoscope and the first photo is one of bad yellow springs with a crack. Notice how they are all yellow. Any help would be greatly appreciated, as I’m new to the Vette world.