Hi Zartan,
As far as I am aware, Marushin and other manufacturers do not use real gold to plate their metal handgun models. I seem to remember seeing an article quite awhile ago explaining what the finish was, but I can't recall the details.
If, however, Hobby Fix state that they use 22k gold then we must assume that they do!
Japanese laws and regulations made it necessary for metal pistols / revolvers to be plated a gold colour identifying them as replica models.
A video I saw recently on youtube showed an old metal modelgun being restored to as new gold colour using liquid chemicals. The commentary & text was Japanese which I don't understand unfortunately.
Owners tend to remove the gold effect to expose the bright silver coloured plating beneath to make the model look more realistic. I removed the gold effect from a Marushin Auto Mag very easily by using Brasso and a soft cloth.
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Cerwyn
Hobby collector of Replica model guns and Militaria.
also member of Living History Reenactment Groups.