Your gun most likely is a Remington but it could be a Whitney (as in Ely Whitney's son).
The Remingtons loading lever is round for about 1 5/8 inches from the front of it at which point it turns into a thick blade looking shape which angles downward to the loading ram.
The cylinder pin has a T style head which is retained by the loading lever but not attached to it.
The Whitneys loading lever is round for a distance of about 3 inches from the front of it where it turns into a rectangular block that is connected to the loading ram.
The cylinder pin is a part of the loading arm assembly.
Either one would be worth about the same amount of money.