yeah i understand, seen and know why series 80 extractors have the plunger cut out, i figured this is what you meant by "thinner".
but i have never seen nor heard of a series 80 extractor breaking in the cut out area, they always break at the tip, where they get the abuse and wear.
i heard that even the new colt 70 series guns still use a lot of 80 series parts, so i wouldnt worry about breakage because of the cutout.