IBM outsourced keyboard production first to Lexmark, and then to Unicomp. Unicomp then later went and bought the patents and everything to spin-off their own products, still with the original tooling.
You'll find a lot of "Original IBM" keyboards that were built by Unicomp in license. I have a Model M4 from 2000 that was already built by Unicomp, sold by IBM with their own branding.