Given that the label was used for "ordinary studio" models I believe you are correct. I doubt if the 1957 vs 1960 date "discrepancy" is significant. It could just mean that the outsourcer still had some of the older labels and used them up before switching to whatever the newer label was. From the picture I wouldn't be surprised if the back is a laminate despite the apparent centre join. Could be a mahogany of some kind. But without seeing the outside it is impossible to say.