1860 Spencer carbine serial number 10403

[Point man]

I am currently looking at an 1860 Spencer carbine with serial number 10403 on both the barrel and receiver. It has a 22 inch barrel with six groove rifling.The crown of the barrel looks fine.All aspects of this carbine appear to original.Could this be a very early carbine or a very well cut down rifle? Any information on serial number 10403 would be greatly appreciated,Point man.