Stall torque for servo, kg/cm?
The normal SI units for torque are Newton-metres.  Torque is a force times the distance from the fulcrum/axis.  The units that you are giving do not make sense (although I have seen them in a number of places quoted for this device - puzzling).  I expect that this is a mistyping of the units on a cheap data sheet.

I would expect that the motor will stall when a weight of 0.8kg is hanging from a 1cm long arm attached to the motor spindle.