just for your information, the black cylindrical part is the knob which is rotated to change the value, mostly people rotate it without knowing and disturb the stock values.
with time and experience some of us have got the idea about the stock values of this resistor, you can serach internet (specialy malaysian forums) for further information also youtube videos.
a multi meter is used for that, eaiterh u can check with by the way of resistance, or by the way of voltage.