If the new plate is case cl`d/blue, to begin,a fadeout with flitz/oil and fine steel wool would be okay ,imho.
Otherwise ,if bare metal,
a quick application of naval jelly to tone down the shine`ness,
and 4/0 wool to taste.
Or cold blue the PP out of it,then naval jelly it back again.

You cant fool any but a fool,so put it up and let it "meld" in its own.