That is: the one MLK Jr referred to in his speech is the mountain from which Moses was allowed to see the 'promised' land, to which he was denied entry, just before he died. The scene is from the very last chapter of Torah, Deuteronomy 34.

The appointment of Joshua (at God's direction) occurs in Deuternomy 31, and no mountaintop visit preceded it.

BTW, as DFM has recently mentioned, there's a preponderant lack of evidence for the events in the book of Joshua being real. On the contrary, the "conquest" appears to have been gradual, generational, and by assimilation. Too bad biblical archaeology wasn't invented until after the Crusades... but I don't imagine GW "Crusader Rabbit" Bush has any idea about that, either.