revolutionary war buttons

So this is one that always made m wonder. I thought some kinda die or mold unfinished. This was dug up at a properly owned by James trenchard. An engraver/die sinker who came up with the great seal and alot of the symbols for this country we still use today.

Hi everyone, I'm writing to you from beautiful NH while I am on vacation. John did a bit of detecting today and found a large amount of buttons and a mystery coin. I do not have my coin book with me, so if any of you can ID this, we would greatly appreciate it. As for the buttons, we're curious...

I found this button while digging around in my parent's back yard. Is it Revolutionary war? Back is solid, looks to be brass. Is it British Navy? Any help would be appreciated. I've been looking for hours!!