We need to see photos.
I've seen mis - roll stamped guns - usually Speed sixs (round butt, fixed sight) marked 'Service Six' (Square Butt, fixed Sight). (I have 3 :shock: )
It would not surprise me that a short barred Security six (square butt, adj. sight) was mis marked. I've seen at least one Security Six mismarked as a Service Six.
It would also be easy to install a 9mm cylinder in a Security six frame - basically interchangeable with the 357 mag. cylinder.
However, I've NEVER heard of an adjustable sight 9mm. We'd need to compare the 9mm markings on the barrel with one on a Speed Six. It would have been possible to buff out the original .357 mag. markings and re-stamp with '9mm'.
But....as we say with Ruger, "Never say 'Never'". :shock:
I've always sort of expected one to show up. Love to see some photos. Need to get a letter from Ruger on it's original factory configuration.
Terry T