The *old school* method of an alignment rack would be something like the old Hunter *Lite A Line* rack which is a 2 wheel rack that only does the fronts.
The head unit is in a pit, the trammels are ground level, the vehicle drives onto them, the two wheel sensors are mounted to the wheels, and the lite sensors shine in the form of a crosshair the lite onto the 2 scopes in front of the vehicle.
These old alignment racks can still be accurate, but given the technology today & how accurate these *wireless* units are...
why go elsewhere?
I just had my truck done recently, it's not twin-I-beam, yours is just a matter of setting the toe, unless your front springs/ride height are creating a camber issue for you and you need to replace/install new cam bushings.