On my chassis, which has never been serviced, one of the 3.3 uF bipolar positions (on the list) is a 1uF 50V bipolar cap, while the other position is not a bipolar cap at all but rather a 10uF 50V polarized cap, and the silkscreen is marked as such that it should be a regular polarized cap (has both the + marking on the bottom silkscreen and the circle on the parts side indicating the negative pole).