Silver Comemorative, Apollo Eleven - Mintmark, or engravers autograph?

Edge inscription reads F.S. 999   0639, evidently a numbered issue.

There is a tiny capital L  near the bottom of the rocket on the first image.

There is rather an official looking NASA device at the bottom of the second image.

There is no information whatever in the little plastic case.

Is this a product of the US Mint, Philadelphia? if so is there an engraver who signs with an L ?

edit to add: not finding it any catalogs. 30.7 grams, 39.25mm

A clue from the UK

https://en.numista.com/catalogue/index.php?ct=exonumia&se=Man%27s+First+Landing+on+the+Moon&e=royaume-uni

https://www.worthpoint.com/worthopedia/ultra-1969-apollo-11-moon-landing-1oz-467457459

Apparently private by the American Medal Corporation.

thanks, that's excellent.