A beautiful NE gun! It has all the bells and whistles and appears to be a late 1700s gun; perhaps barely into the 1800s. It has an early lock much like the English round faced locks popular in the late Colonial era into the Rev War Period. I can't see any carving, but then they never had much anyway, usually at the rear of the barrel tang. These guns would be a delight to take into field or forest. Light and they aim very well. Good on you for finding it and thank you for showing it here so that we can all admire it.
Dick