The sleeves were basted in before they were sewn in by machine. The basting stitches were left in. The seam allowances are very narrow, only about a quarter inch as opposed to the half inch used for the rest of the bodice.
Both sides of the facing were pieced near the center front. The buttonhole at the waist was also faced with ribbed silk. The rest of the buttonholes are just in the satin and lining.
On the right, the dark line shows where the satin joins the ribbed silk. The lining is folded over and whipstitched to cover the join, creating a slight ridge which shows as a shadow in the picture.
On the left, the collar facing. The ribbed silk has its edges folded under and it's whipstitched into place.
A detail of the black linen underlining in the lapel.