Mr. Green: I think so...unless they suspended operation for some reason. I had a SG produced after 1960,and it was likely a Special Order rifle.....so I guess someone was working there.
The thing that's curious about your rifle is that the Rock island auction description says it was made in 1957 (or did I misread that?). Yet you indicate it was made in 1961.
Was it maybe built on an action made in 1957(per serial number) but the rifle itself was produced in 1961?