Thanks for the extra pics Birdie, your top is an interesting one.
The photos indicate a home sewn garment, with hand stitched button holes which suggests an earlier date. The hem also looks earlier, but as mentioned, it could just mean an older seamstress who is using techniques she honed in her youth. Even now, I prefer to hand stitch my button holes as I dislike machine sewn ones (this makes me very unusual but I personally prefer hand stitching to machining).
More information please:
Can you please provide a photo of the front of the sleeve opening binding: basically, I wonder if it is top stitched or sewn and then folded back (which is the older technique and the one I favour).
Also - can you please photograph any seams that are not finished off with the selvedge, eg, how are they finished, with a row of stitches, pinking, serged or raw?
The fabric is reading like a heavy linen or cotton, even a bit canvassy.
I'm thrown by the styling though, and this may not be the way it was intended to be worn. Can you please provide bust, waist and hem diameter measurements?
I'm trying to see this as a '40s top and the shape is throwing me off. I wonder if it was a maternity top or a maternity dress that was recut into a top? The hem is old style though: can you tell if the same thread has been used for the hem as for the seams?