Being an ex pressman, printing equipment technician, I have some insight into printing. Gold colors can be printed via the offset process with gold inks. gold inks have metallic particles suspended in them so they present some issues with cleanup of the press. The results you can get from gold inks are gold-ish colors but if you really want gold color you need to go into foil printing. You see gold foil printing on greeting cards, wedding cards etc. this foil is very thing actual gold leaf, it is similar to the lettering you see on the front of many old businesses. It also comes in colors like red. It is applied to the paper by hot stamping. This means it is printed letterpress, not offset, inkjet,laser etc. to accomplish hot stamping or letterpress printing you need lead type, or in the case of a logo or picture this was done by creating a wood block which was covered with a lead plate that had the image on it , with the parts to be printed – a raised surface. There are companies in existance that have the ability to produce raised metal printing plates from photograpic images. The press used for this type of foil printing was a letterpress, which is a press that opens and closes with pressure. You probably remember John Boy Walton treadling his press to get the newspaper out. I have such a press in my back yard weighs about a ton – it’s too big to get in the house!
To do gold foil work the press needs to have an attachment to heat the type or plate to make the foil process work. there are a few companies that specialize with this type or equipment often for wedding and greeting cards. Presses of this style were in common use when most of the radios were made and some are still in existance for certain purposes such as die cutting boxes. Because of the cost of setup involved in hot foil printing it isn’t practicle for a (one off) dial, but I just wanted to point this out as you often see this sort of gold foil work – for example used on some dial faces.
printing black over gold colored foil might make for some very good results but I haven’t tried, I think this is the best alternative if you want it to really be gold and shiny.
so with Letterpress being common in the days our old radios alot was done this way. for example: cutting the backs out to a specific shape and printing on those was most likely done on letterpress.
One other interesting process that will produce a raised gold image is thermography. You have probably seen business cards done in raised print. this is done by printing the cards on an offset press and then sprinkling a plastic powder in the wet ink. The wet ink holds the plastic powder and the rest is vacuumed back off. then the sheet goes through an oven giving sufficient heat to melt the powder. Usually clear powder is used and the color of they type is the ink color, but it is possible to use gold or yellow ink with gold plastic powder. I used to do this as a job , and had some stunning results printing on black shiny paper with the gold powder. Same drawback though with the cleanup time. The gold powder is a job to clean up so it was done only once a week to keep this cost down.