Not enough information to answer either question.

The Spencer MAY be a Model 1865 since Model 1860 Spencer Carbine serial numbers began at approximately 11000. The 1860 is the only true Civil War Spencer Carbine as the Model 1865 came on the scene after the war had ended. Look on the top of the barrel breech for M1865 to confirm the model.

I don't have enought fingers and toes to enumerate the various models of Colts that could have that serial number. You need to offer much more information about the gun.