It could just be a cheap knock-off. I doubt a real Gloria Vanderbilt shirt would have a logo right in the middle of the front: that seems kind of tacky, especially for the late '70s, which was before wearing logos was popular. IIRC, that concept started with IZOD and maybe Ralph Lauren, but now has been distastefully maximized by companies like UnderArmor and The North Face ( for the last decade or so owned by Vanity Fair). I don't believe that shirt style would have been unusual in the late '70s. It's made to look like a two-layered kind of thing. Synthetics like polyester especially were popular. In those days, scrubs were plain and nurses, dental hygienists etc. wore white. I don't believe there were labels on the inside seam in those days that indicated fabric content and washing instructions. Potentially, there would have been a label at the neck, but those can be itchy and may have been removed. It would be easy to tell from looking at the seams whether this item was home-stitched. It does not look home-stitched to me. If the fabric is a knit, that would seem even more unlikely to me, since it would be hard to get that neck detail with a knit. I know from sewing knits myself in the '70's. Holyoke Hospital is not too far away.