George Moller, American Military Shoulder Arms, Volume III,  claims Whitney assembled rifles out of inspector rejected parts and surplus from their large production of  Model 1841 Rifles under federal contract from late 1840 to early 1860.  Whitney also purchased surplus and rejected parts of the Model 1841 and M1855 Rifles from federal production as well.  These rifles, resembling the Model 1841 and Model 1855, were referred to as “Good & Serviceable” 2nd quality rifles and were sold to states, militia and various arms dealers from 1846 to 1863.  There are records of sale to the states of South Carolina, Mississippi, Georgia, Ohio and the federal government.  At least 990 were sold to states that joined the Confederacy. 

Total actual production is unknown but records show at least 1,968 were sold and production may have exceeded 2,500.  Some were fitted to socket bayonets, some were fitted with saber bayonet lugs with a 1 inch guide key and some were fitted with Model 1855 style saber bayonet lugs with no guide key.  

There are a lot of unanswered questions about what saber bayonets were actually used with the "Good & Serviceable" rifles assembled by Whitney during the built up to the US Civil War.  Apparently most of these rifles were made with surplus and salvaged US Model 1841 or US Model 1855 Rifle barrels.  Therefore, the associated bayonets would have the same muzzle ring diameter of around 22.8 millimeters for either rifle.  It would be easy to say that bayonets with a guide slot were for Model 1841 Derivative Rifles and those without a guide slot were for the Model 1855 Derivative Rifles. But with all of the parts and pieces going on with the "Good & Serviceable Rifles", is this a "for certain" assumption? 

For now, I have decided to list all the bayonets that are suspected of being for either model under the heading of Model 1841 Derivative Rifle.  At least until more information is found that enables one to tell the true difference.