No, one does not mean the same.
"The LORD our God, the LORD is one [echad]."
"Echad" means one of plurality. Let's use "one" in a sentence that shows plurality:
"The people spoke with
one voice."
Now, if what you say is true (that "one" means "the same"), here's a few questions for you:
Did all the people use the same set of vocal chords to speak? Or each individual person use their own vocal cords to say the same thing? Was there just one and the same voice speaking? Or were there multiple voices saying the same thing?
What about this verse?
Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh. - Genesis 2:24
http://www.biblegateway.com/passage/?search=Genesis2:24&version=NKJV
"Echad" is used in this verse also, showing a plurality in the "oneness" made by a man and a woman coming together in marriage.
Does that mean they are the same person?
I tell you NO, OF COURSE NOT!
One does not mean the same.
And where does it say that He obeyed God and it was accounted to him for righteousness in Genesis?