Frank Sellers Sharps book was great in its day, but there has been a lot more learned since then. If you have it, use it, but understand that there are likely some errors. This forum is a much better source of info. If you think you have a Sellers ID, go ahead and use it and ask if anyone can add anything, or make corrections.
Roy Marcot is heading up a team working on a multi-volume set on Sharps and I think that two are already done and the third is at the printers now, with one or more additional still being worked on. Roy will undoubtedly include a lot on the ammunition.