It would take a heavy plate to fill in the stampings. That S&W had definitely been refinished, but the finish could be chrome, as this was done in the mid-Twentieth Century. Nickel plating as was done by the factory does give off a yellow cast under certain lighting. Often a gun that is being prepared for refinishing by an unskilled gunsmith or owner would be buffed to eliminate pitting, etc. and that would remove stampings as well. You may have seen these and it can give the impression that the plating filled in the stampings.

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Gary
SWCA 2515