A few minutes with Google, which you also could have used to correct your "impression", yielded this site:Quote from rcanfiel:...I was under the impression that people turning in their gold got th new rate...
http://www.conservativeusa.org/eo/fdroosevelt.htm
Click on order 6102. I linked the entire list so you could give yourself a history lesson about the "great" FDR, who used a crisis to dramatically expand the control and size of government. While you're at it, please review 6556 and 6560, and don't miss 6814 confiscating silver in 1934.
Now as to the official price of gold in 1933, it was $20.67. See http://www.measuringworth.com/gold. Leave the US Official Price checked and put in whatever date range you want to cover 1933.
For theories about gold as it relates to monetary policy, there's probably no better site than that of the master at http://www.mises.org.