Piece came flying out of watch

In focus picture would help. Looks a bit like part of the hairspring regulator, although that part seems to be there. Most of that assembly is in shadow and hard to make out. The watch is badly out of regulation as it looks like it is all the way on the fast side.

Other ways it looks like setting parts, but those are mostly under the dial, and the watch would have to be taken apart for them to have a way out of the case.

Could be the proverbial 'extra' part. I find it interesting how the plate layout looks like a lot of the A Shild stuff I have. I guess there are limeted ways watches were made in the 1920s and 1930s. The finish looks nice.

Blue Jewels seem to often denote Japanese delivery for pocket watches, this is something that @Modest_Proposal is doing a little bit of research on.