No... that is not "offset" that he was asking about.
The offset, measured in millimeters, can be negative or positive, and is the distance from the mounting surface to the rim's true centerline. A positive offset means the wheel is front of the mounting surface, closer to the center of the fender; a negative offset means the wheel is away from the mounting surface and projecting from the fender. Offset affects the
scrub radius of the steering and it is advisable to stay within the limits allowed by the vehicle manufacturer. However, if tires are fitted which are significantly wider than those specified by the manufacturer, a compromise may have to be adopted whereby a wheel with less offset is used to prevent the tire rubbing on the suspension.
Those trucks with tires that stick WAY out from the fender? yeah.. negative offset, to prevent tire rub. (actually, commonly just.."because they want it that way"
The SVTs rim offset - 40mm
He was asking about the 15" rims inner diameter and whether or not it would clear SVT calipers/rotors.