The reason I asked the question is that the second ship could be further away than range 3 and still be used for "Barrage of Fire". My understanding of the forward firing arc is the front 90 or 180 degree area depending on the ship. If the first ship is at range 2 and then you add the base of the primary ship and measure range 1 back from it, then the second ship with be further than range 3. Which by definition of "Forward Firing Arc" is defined by the angle and not the range to the target.
Still doesn't matter, though.
The second ship is not making an attack by the rules, it is just lending its primary attack value to the first ship. As you said, it's only concerned with the firing arc, and not the range of the second ship to the target.