Gold conducts electricity much better than does tungsten. So I believe that an electrical conductivity test could tell the difference between gold and gold-plated tungsten.
That likely wouldn't help either, as the outside would be actual gold, which will conduct the electricty as expected.
My DIY pinpointer tests the inductive properties of the coin without touching it. Tungsten and gold are way far apart on frequencies - a high whistle and a low whistle- easy to detect- tested it on fakes already many times- well duhhh