Used to be a vintage gun parts seller on the East Coast called " Stoneman of the Delaware". Actual bought some oddball breach-block parts from him for a 1st Allen Conversion Springfield. That was about 25-years ago. To my understanding, Stoneman had much of the residue parts left over from New York's, Francis Bannerman company.

Purchased nipples for 1861 and 1864 Springfield rifled muskets too. Remember that those arms were often encountered with corroded nipples due to improper cleaning. Believe too, that some might have been reproduction parts. With a little aging, the components blended right in.