just taking a look but I think you are looking at the 321st Glider Field Artillery Battalion (GFAB). Here is some information on the unit.
Dear Mr. Vernier,
Thank you for posting your request on History Hub!
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 may include records of the 321st Glider Field Artillery Battalion, 101st Airborne Division. We also 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 68 file units about the 101st Airborne Division. For more information about these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
Photographs of various U.S. Army, Navy, and Marine Corps activities dating from 1940 to 2007 are in the custody of the National Archives at College Park - Still Picture (RDSS). Please contact RDSS via email at email@example.com. Their web site is https://www.archives.gov/dc-metro/college-park/photographs-dc.html.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT2 and RDSS. We apologize for this inconvenience and appreciate your understanding and patience.
We also searched online and located the following sources and/or listings of collections at other institutions relating to the 321st Glider Field Artillery Battalion and/or the 101st:
There also have been many books that have been written about the 101st Airborne Division as well as books about specific campaigns such as the Normandy Campaign which may be located through retailers and libraries.
Finally, you may wish to contact the National Museum of the United States Army, the National WWII Museum, the Don F. Pratt Museum, the 101st Airborne museum in Bastogne, the Airborne Museum at Sainte-Mère-Eglise, the Airborne & Special Operations Museum, the U.S. Army Artillery Museum, and the 101st Airborne Division Association.
We hope this is helpful. Best of luck with your research!