I wonder if the stainless sights had anything to do with the early days stainless guns -- when it was a novelty. I can remember magazine gun writers in the 1970s taking stainless guns (and the 66 was a prime candidate) and throwing them in lakes, burying them in mud, throwing them in boat bilges and all manner hostile environments and then recovering them after a period of time, hosing them off and seeing if they would fire (didn't read an article where it didn't). I'll bet the stainless sights where in response to this kind of abuse that seemed to be rampant at the time.