A 1600s Spoon, Perhaps?

[SwiftSword]

Here's a puzzling find from eastern Massachusetts. I've pulled over 100 spoons so far and know a run-of-the-mill plated spoon when I see it. This is different. Between the fig-shaped bowl, the symbol at the inside top (I don't think it's a hallmark), and the notch where the handle detached, this looks pretty old to me. The surface isn't plated. Much more like a wash, or even like tombac. Underneath the silvery layer (which only has a microscopic thickness) is a thick, crumbly layer of powdery green corrosion.
I am cautiously optimistic that this is indeed an ancient spoon, as I have found 18th century artifacts nearby. My city was founded in 1642, so it's not impossible. But I've learned to control my wishful thinking and am seeking an expert opinion. Any ideas? If not, do you know of a spoon expert?

[Valens Legacy]

I have no idea about the spoon but it does look very cool, great job on finding it.

Good luck on your next outing.

[Geologyhound]

Don’t know if this will help or not - Trademarks on Base-Metal Tableware https://sha.org/assets/documents/Trademarks on Base-Metal Tableware.pdf
 

I don’t know know what to call the symbol, so it may take a while to scroll through the list.

[kac]

Looks like silver plated. Very early dinnerware were usually pewter. Much of silver pated items were later 1800's -1900's

Leaded pewter was pre 1770's and usually softer and very dull looking.

You try looking up the makers mark?

[PimentoUK]

It's definitely old. It does resemble Tombac, that has corroded heavily.

The makers mark ( touch mark ) is three alternating keys, inside a beaded/dotted circle.
Similar items for guidance:

PAS spoon1

PAS spoon2

If you fancy browsing through thousands of spoons, this link should work:

lots of spoon