Your gun would most likely have been accepted in January 1864 (a quick search of the forum tells me that SN 48836 was in December 1863 an SN 56494 in February 1864)
The final acceptance mark is a cartouche on the left grip, they can be very faint, the only part visible on mine is 3/4 of the outline so look closely beneath the grip screw.
/A