I would try contacting the Army Corps of Engineers museum they may have someone there that is knowledgeable pertaining to unit histories.
Dear Mr. Golden,
Thank you for posting your request on History Hub!
Your research into your grandfather's unit should begin with the following two entries, (note that these are not digitized and therefore not available online):
We searched National Archives Catalog and located the World War II Operations Reports, 1940-1948 in the Records of the Adjutant General's Office, 1917 - 1985 (Record Group 407) that includes records of units during WWII. For more information about these non-digitized records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
We searched the National Archives Catalog and located a series titled Unit Histories, 1943 - 1967 in the Records of U.S. Army Operational, Tactical, and Support Organizations (World War II and Thereafter) ( Record Group 338) that includes the file units for various Military Units. For more information about these non-digitized records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at email@example.com
For further information see this blog post: WWII Military Unit Records at the National Archives
We hope this is helpful. Best of luck with your research!