Nope, a kg is indeed a unit of mass. A unit of weight in metric is Newton.

...Grams are absolutely a measure of mass. You body has the same amount of kg on earth as you do on the moon and beyond. Pounds is a measurement of force and will change depending on elevation from the earth.

A kilogram is a unit of mass. Just read the definition of it

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>"The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015×10−34 when expressed in the unit J s, which is equal to kg m2 s−1, where the metre and the second are defined in terms of c and ∆νCs."[1]

The SI unit of force a 1Newton that in SI base unit is 1 kilogram meter / second ^2