A bezel is the ring around the crystal. On a worn watch, the part people change is usually the insert, the marked ring that sits in that bezel, not the case itself. A tachymeter insert, a dive-time insert, and a plain polished ring are different readings of the same seat.
Look at how the markings have aged, how the insert is held, and whether it rocks under a fingertip. A loose insert is a description of a part. It is not proof about the name on the dial.
The modifications index lists this note beside the bracelet and the hand set. The word tachymeter, when you only need the definition, is in the glossary. The function that uses the scale is the chronograph.
The insert, the click spring, and the alignment pip are in Bezel inserts.