Replacing the instrument cluster lens
Disconnect the battery. Disconnect the speedometer cable, unscrew the 6 instrument panel screws. Carefully slide it back. Disconnect all the wires and bulbs, if you don't have the electrical scheme write down first what goes where! This is the view you will have.
Here is the instrument cluster after removal. The holes are for the light bulbs, 4 instrument lights, 2 for the indicators and the high beam in the middle. There are 11 contacts in total.
You can read the date stamp: october 8, 1965. This is correct with my car's built date, so the dash is original.

8 screws take the whole cluster apart. The back in white holds all the meters. The little blue covers are for the instrument panel lights. Most of the time these are melted. In my case they are in perfect condition.

The bottom part is the black camera case/chrome unit which also holds the lens.

Now that everything is taken apart it is time to give it a good clean. And the replace the old lens with the new one.

Here it is, the new lens gives you a better vieuw on the gauges. The lightning also has improved.

Re install all the wires and bulbs, slide the cluster back in, connect the speedometer cable and reconnect the battery.