I'm having a super hard time dating this sweater top. I got it from an estate where the woman knit a large amount of her clothes, and most of the pieces were from the 40s-60s. I can't figure out what decade this is from though - if it's on the earlier side of those or as late as the 70s. It feels like a synthetic/rayon knit and has small tubular elastic in the neckline which I've attached a photo of. Thanks!