Didn't care to extrapolate much on this as it was my day and had so much time to burn.
For starters, when steel glows red it leaves behind a black scale, think of a blacksmith here or new hot rolled metal when you get it.
Think of turning colors like if you cut too fast with a drill press or a lathe for example and get a colored chip coming off, nothing glowed red hot to achieve the steel to change color in this fashion.
Turning colors happens much before this, as a red glow starts at 1,000F up to 1,500F goes to orange at 1,600F to 1,900F and yellow 2,000F+.
Here's a color chart giving the degree level reached when observed.
View attachment 379595
Here's a pic of my 660 that made 2 test cuts besides idle time and tune.
View attachment 379597
So with this little bit of knowledge it would/could quite possibly be plausible that the coloration on new saw rod ends was from the run time at the factory and not from manufacture, as it doesn't take a long time for friction to create heat and I would hazard to say that a tolerance mismatch of minute proportions could do this in short order.
It makes me wonder what the manufacture would say if a new saw with this "calamity" was put forth as a warranty claim what their response would be, this should tell the tale in short order one would think.
Personally I've only noticed this phenomena in used equipment as the number of new I get into is quite low in comparison no doubt.
But really the question is will it run? So far from what I've seen running and what my saw and others are returning to service, the answer for now would have to be a yes. Could there be long term ramifications? If so I would think that we would see the failures on a regular basis enough to come to a reasonable conclusion that it had, lacking them is much like how many licks are in a tootsie pop, either the answer is three or the world may never know.
We can now see the massive amount of heat created in your 880 example, which would have to be considered relatively unique as far as such a failure goes as how may get to see such a rarity, which had to be some sight to see indeed. Any pics by chance?
Alas, if it's just story time we're after, I once knew a gal that turned the color of every rod end she ever met, this however doesn't advance the subject matter at hand any more than automotive parts being made does though.