I came across this pattern on E-bay a short while ago. It is clearly at least 50 or even 60 years old judging by the picture alone. But there are other clues that tell me that this is either a WW2 pattern or shortly after. It is very economical on paper and printing.
There are no markings on the pattern pieces at all, just punched triangles and notches. The pattern pieces are identified only on the envelope and the instructions could leave you wondering why you ever complained about modern pattern instructions not being clear – until you have a good look and see that there is quite enough to get you through- and all on one sheet.
Clearly they assumed that seamstresses back then knew what they were doing – and by and large they did. Home Economics were taught in all Secondary Schools and sewing your own clothes was quite the norm. It would be interesting to know if it can be dated.
On that topic, if you haven’t already, have a trip over to YouTube to watch “Sewing: “Pattern For Smartness”  -Simplicity” you might find it a bit coy or rather sweet – depending on your viewpoint. It was clearly filmed in America, and I know from experience that if it was shown over here there would have been loud wails – where do we get the fabric? Materials were scarce, rationing was still well in force and life was a little bleak to say the least. Such things are not always remembered in the rosy glow of ‘vintage’ – except by us that are!