Q:

Was Plato influenced by Moses?

The 2nd century Christian apologist Justin Martyr is known for defending Christianity to the Platonists of his day.  In his First Apology, he claims that Plato's understanding of the creation of the world depends on Moses:

And that you may learn that it was from our teachers—we mean the account given through the prophets— that Plato borrowed his statement that God, having altered matter which was shapeless, made the world, hear the very words spoken through Moses, who, as above shown, was the first prophet, and of greater antiquity than the Greek writers [...] Both Plato and they who agree with him, and we ourselves, have learned, and you also can be convinced, that by the word of God the whole world was madethe country. 
I think that Justinus tried a bit to revise history in order to strengthen his message.  

A:

At least one well-respected, contemporary scholar of the Hebrew Scriptures, Margaret Barker, argues that Plato knew of them, though she acknowledges her view as in the minority:

The early apologists, both Jewish and Christian, maintained that Plato learned from Moses, that he was Moses speaking Attic Greek. The most notable of these was Eusebius of Caesarea, who, in his work The Preparation of the Gospel, argued the case in great detail and listed all those who had held such views before him. Eusebius and the other apologists were probably correct. 
My reconstruction suggests that the priests of the first temple knew an invisible, heavenly world on which the tabernacle or