FWIW bolt threads in the US weren't standardized until post 1811 after John Hall patented his breech-loading Hall rifle. Threaded bolts from his 1st prototype, never mind 1st model, will fit his firearms from the 1840s.
Mr. Hall was a more ingenious machinist inventor than he was a firearms designer and he also developed the milling machines, balanced power driven (from water wheels) systems, standardized gauging, standardized thread forms and the micrometer that will still use today. He designed these all to make his Hall rifle as the truly interchangeable-parts item made in the world.
In the US, prior to his standardized of gauging AND thread forms, parts may only have been interchangeable with those within the same manufacturing run, such as with Eli Whitney's cotten gin. When those thread dies finally wore out, new ones were made ... but they that may not fit the newest ones ... or the previous batch/run.
Therefore, for that missing bolt on that blunderbuss, it is highly unlikely you'll be able to match that thread ...