The originals were/are forged. For about the first 47 years, the 1100 used the same extractor as the 870. Autos tend to be harder on them, so they made the one on the 11-87 thicker. In 50 years, through 11 Model 1100s, and 6 Model 870s, I broke one extractor in my 1963 Model 1100 in 1982.
I have noticed a lot of people install new extractors and do not shape the outside of the extractor to approximate the bolt contour. This often leads to a mark in the receiver where it hits it when it comes back.