They don't replate the metal, they replace it. To replate the metal would be too costly to do on a bag by bag basis. They also replaced your chain, they didn't replate it. If you have the 22k gold plated older hardware, they will likely replace it with the current hardware, so be aware of this.
If you asked for all metal hardware to be replaced when you took it in, that should have included the chains and the turnlock or CC closure (which is what I'm guessing you are calling the metal plate).
This is why I don't want the hardware to be replaced on my 11 series jumbo. I think I'll jut get it cleaned instead.
