We changed the scales, but that’s the basic meter.
To get it apart you need to remove the meter from the main chassis, then the front section unclips; you can just pull it or lever it off. This exposes the movement and the little wire-ended lamps.
For general interest, later meters (without the reflective strip on the face) were held together with transparent tape across the back…. as are most meters nowadays.
The later ones use a single wire ended lamp rated at 24V.
Nowadays in TFPRO we use a very similar meter. The lighting is driven direct from the low voltage (15V) AC on the mains transformer direct to the lamp. The undervoltage keeps the temperature down, provides a nice subdued light and the lamp lasts for ever!
I have experimented with LED lighting, but it just does not look as good. 