Levi Strauss 501 Jeans, button front

Rare vintage Levi 501 jeans with button-up fly in like-new condition. Appear to be for women but not sure. Buttonholes are inside front, and when buttons are fastened it appears to be a fly front. Straight leg slightly tapered at ankle. I would call them indigo blue. Lots of tags but none state size, no size indicated on leatherlike patch on back, I have estimated size. 100% cotton, made in China. 40" long, waist 16". Back pockets embroidered in orange and yellow. Three front pockets, belt loops. Label reads Levi Strauss & Co., San Francisco, Cal. Original Riveted Quality Clothing 501.