In the sixties, some double cloth fabrics were bonded together instead of having a 5th set of yarns. Also, the binding on the seams was very popular; this is the Hong Kong finish.
My thought about the fabric is that if it is a bonded double cloth, it is probably sixties; but I'm not sure that you can tell with damaging the garment. If there is a place that you can remove the binding on the seams--perhaps in a sleeve, you could see the fabric edges.
The buttonhole is hand made. Claire