I assume you are referring to the experimental Sharps Rifle Musket, model 1870 Type II, of which 300 were made.  I don't know for sure about the bayonet, but these Sharps rifles used the standard US model 1868 Springfield barrel with a collar added to the breech end in order to mate to the Sharps receiver.  The forend used a US model 1868 nose cap as well.  One can speculate that the standard US Springfield M1868 rifle's bayonet would would fit the experimental M1870 Type II Sharps rifles as well.