LS is the designation for "Long-Slide" and you are right they are rare especially in stainless. Last one I saw in Gunbroker went for $400. It appears customers looking for an OSS are buying because they have the five inch barrel and some prefer the sights on the DS.
i've been contiplating a trade in of one of my pt709's for a 24/7. I don't have a 9mm range gun. All my guns are owned with specific purposes. I have another 709ss that I keep in my desk while working. I'd like to have 24/7 9mm with light as a replacement of the pt709 and it will make a nice range run.
We have a gun show here coming up and i'm going to being the extra 709ss with me (has over 1000 flawless round through it) and see what I can get.