The commercially sold plates, as purchased by officers, are often described as more detailed, etc., and featured a "silver wash" to color the wreath, etc. The plates issued by the Army for NCO sword belts and cavalry saber belts had a cheaper "nickel wash" coloring the wreath, etc.
For a replica plate, you might get a metal wash electro plate kit to spruce it up, or perhaps try some kind of metallic paint.
I've always thought the applied 'silvered' wreath was an nco plate while the officer plate was a solid cast plate with a silver wash. RedRover's info is teaching me differently. Learning all the time!