The yarn content could be a clue to went it was made. Can you snip a bit off and do a burn test? If it was knitted in the 40s, I would expect pure wool. Pure wool wouldn't rule out a later date, but if it's synthetic or a blend, it's likely to be later.
The cuffs look to me as though they've been designed to be folded back, so the lower portion is deliberately slightly looser, or has become stretched by being folded back. Sometimes cuffs have a line across them for folding, achieved by knitting a row or two on a smaller needle to create a fold line. I don't know whether this was done in 40s patterns, but it may well have been.