You look at it

If the tire on the driver side is sticking out and the passenger side is tucked under the flare, an adjustable track bar will help. If you walk back and forth and can't tell if one is sticking out more than the other... then you really don't 'need' one.

Pushing the axle to the passenger side a bit will help prevent the driveshaft from rubbing on the gas tank skid as well; becomes more of an issue when you remove the sway bar and put on longer shocks