I needed gauge rings for a TR4A I am building and for the small ones I found some metal transfers that were easy to apply and look good. This is a current ebay listing for them. I used the 3rd largest rings.
The large gauge rings are PE. The Dash gauges, wood, ash tray, glove cmpt. outline and two small lights between the Spedo and tach are a color print I composited using a scan of a wood sample and photos. The rings give it a believable depth.