I don't think that the way to the Westgate existed prior to the Elves founding Eregion. If you think about the way of the company it looked for a long time as if they wandered through a very simple tunnel system with no much choice of direction. Only when they aproach the eastern area of Moria things become more complex. In addition the dwarves did use the redhorn-pass frequently. Otherwise it wouldn't have gained such a bad reputation. Why would they have used the pass if they had an underground way?
I think that the passage quoted means that not only tha gate was build at that time but the entire entrance and the way to reach it.
Respectfully
Findegil
|