The mechanism of highly enhanced short-ranged molecular fluorescence of dyes on thick tabular Ag island films (TAIF) was examined further by studying how the overcoating of a very thin Au film on the Ag nanoislands affect the fluorescence quantum yield. The Au-overcoating drastically reduced the fluorescence quantum yield, but did not seriously change the dye-to-mental distance dependence of the quantum yield. We also found that the fluorescence quantum yield had a good linear relationship with the scattering efficiency of the island film with or without the Au-overcoating. These results confirm that the enhanced fluorescence stems from the rapid dye-to-metal energy transfer followed by the emission from the resultant local plasmon-like oscillation of free electrons.