There is a design/material issue with 24-105L lens (apart from the aperture flex cable which snaps after some years of use). The red ring is a brittle plastic ring which have some chance to spontaneously crack and fall off. I don't think all of the are intentional, at least I have seen / owned 2 24-105 lenses which the red ring cracked by itself.
Of course auctions of this type would not attract the red ring whores but apart from partially weakened weather seal around the red ring/focus ring, the lens performance is not affected.
That being said, the 24-105L is dubbed the 'kit lens' of Canon entry level FF cameras, don't put up your hope too high that it gives the best construction because it does not.
Also, is a red ring really boost your ego?