Can someone please help me date these stitches and seam finishes?

Please post pictures of the whole skirt, including any labels. Seams and hem finishing is just one part of the picture, and techniques often span many decades.

It has a lace ribbon hem, which is an old fashioned technique. I can't quite see what's going on with the lining seam, possibly a wide zigzag machine stitch, alongside straight stitch?

 

I'm thinking maybe machine straight stitch with handsewn overcast stitching to reduce fraying.

As Ruth says, it's important to consider the garment as a whole. A skirt made yesterday could have the elements shown, if the skirt was not commercially made.