Thank you for posting your request on History Hub!
A search of our catalog returned the following series:
QMCO-520 - 520th Quartermaster Petroleum Supply Company: Unit History, 03/14/1950 - 12/1950
While the title puts the dates of the records at 1950, and I can find no other unit history file for the 520th specifically, you may find some useful information within that series, or through an inquiry to textual reference at College Park, where these records are stored. You can reach them at: Archives2reference@nara.gov
I hope this is helpful in your research!