I would search the bay for a movement. The copper colored FEF 390's are not to expensive if you know what to look for.
The way I did it, learn about the different Tudor references with a FEF 390 caliber.
Search for the tudor ads where the movement is not visible and ask the seller what reference the watch got.
There is a Big chance you get a 390 for cheap.
The rhodium plated 390's is a different story, they are harder to get and to my knowledge not to be found in regular Tudor's.
My 7924 has a rhodium plated FEF 390 caliber.
Maybe I have a spare copper colored FEF 390, I will check it tomorrow.