I use non quilting cotton in quilts for myself. I am not a prewasher when using regular new quilting cotton, but when using other fabrics I always prewash to make sure they will survive the washing machine.
Any fabric that was used in a curtain on the window side, like the lining I would be VERY suspect of sun damage to the fibers, and would probably only use them in a wall hanging or as a permanent liner for sewing crumbs or stips