Hello Joel,
4.1V seems ok. As soon as you take the cells out of the charger they will drop to 4V within an hour anyway. Their nominal charge is 3.7V, but they are usually charged to 4.2V. That is the maximum. The 1000mAh you get is a bit low, though it is normal that you get less than the rated capacity since you never discharge them below 3V, otherwise you risk destroying them. When I charge three 18650 cells, place them in a holder and don't use them for a few days the voltage drops to about 11.5V, and that is normal. I still get a lot of operating time from three cells, even with my KX2 drawing 150mA. Using the MTR I never seem to be able to discharge them (35mA)! Used laptop batteries are everywhere. They should all have removable cells, but instead, millions of good cells are thrown away because one or two went bad in the pack, what a waste.
Gil.