Remove it from the board and follow the diagram to measure the individual sections. Pins 1 and 5 should be one and pins 1 and 4 should be the other. If they are both equal, you should be able to find a stereo or dual pot with the same values. However you have to figure out if they are linear or log. If the values are different, you have a problem!
Like someone else mentioned, why do you think this is faulty anyway? It may need cleaning if at all, which is easy once it is off the board.