Being moved by the spirit is not the same as indwelt. Balaam;s donkey was moved by the spirit to talk, the donkey was not indwelt. The spirit can be moving in a person, without indwelling him. Movement can come and go, indwelling is forever.That is not correct. People in the OT did have the Holy Ghost, and there are plenty of references to it in the Bible:
2 Peter 1:
19 We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts:
20 Knowing this first, that no prophecy of the scripture is of any private interpretation.
21 For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost.