Grip frame of a single seven?

Ok, I have read all the information on the Ruger Grip frames.
Would like to know about the Ruger Single Seven, what years were they produced?
Were any of them produced with the locking GF?
I see there are no frame extensions into the frame on these.
So are the GFs on the Single Sevens the same as the NM Vaqueros and the BlackHawK flattops?
They also do not have the extensions and use a small grip panel. Dont know about the single Sevens.?
RT

Single Sevens came, I believe, in late 2014. They are current production. Ruger phased out GF locks in 2012/3, to my knowledge no S7s have GF locks (I have a pretty early one, no lock).

The S7 is built on the Single Six frame; grip frames that fit the S6 will fit the S7. I don't know if the smaller XR3 frames fit as I don't have any; I do know a birdshead GF will fit, as I have one on my S7 (not the current production birdshead model).