Scratched, faded or even cracked, whatever the problem with the tacho assembly it is usually difficult (impossible?) to rectify. Fitting this new, top quality NOS component will restore the appearance of this area of the machine.
Alternatives you may wish to consider:
Repairing the old one is just not worth the hassle.
It is sometimes just easier to fit a new part.
Add as many parts as you wish to the same shopping cart, new speedo and tacho cable for example, and still only pay the same single fixed price shipping cost.