I have a question. Would this also show right front inset as lead ?square the kart (wheels straight foward) the best you can... then you put un-bent rims without tires on front and rear (right side)... take a 4 foot level and place tight against the rear rim the rim in the front should have a gap if its same distance in the front and the rear of the front rim then no lead if there is a difference you can see if there is positive lead or negative lead... my 2008 element had 3 inches of positive lead within the front to rear in its normal position. Now this is only one way to do this as there are several ways such as a string line and even expensive laser tools. You can see clearly as the axle is straight in karts and the rear wheels will be pointing outside as if going down the straight away the wheels are pointing toward the wall.
Because the front tire is inside the rear does not mean it has lead. It could be that it is set in towards the left.I guess I don't know what you mean hopefully someone else can answer that for you