Pagan priest
SOC-12
From this, it would seem that to use a Jump Gate would require that a ship have an operating Jump Drive, but would not necessarily require the ship to expend the fuel associated with making the jump. Fuel use would be standard for Power Plant operation for the period. Which would make the use of Jump Gates restricted to jump capable starships, but could be used to allow a J-1 ship to jump several parsecs.Here is the text from the last paragraph of page 35 of the original JTAS #24 (see below).
While you are correct it does not call out lanthanum for the jump grid (network of wires in the hull) in the hull (and on page 36 discusses the lanthanum jump coils in the drive itself) it most certainly does state that the wire network is required "to maintain the jump field", and that damage to this network is "a primary cause of the loss of ships in jump".
Written by Marc Miller himself, and published long before anything for MT was published by anyone!
When I have thought about this in the past, I have considered using the X-boat routes as the points connected by pairs of Jump Gates, rather than allowing a Jump Gate to simply fling a ship to any point within range. Thus, systems not part of the X-boat system would still need to be serviced by ships traveling through their own onboard Jump Drives.