Found some annual unit history stuff please follow the links
Dear Mr. Morris,
Thank you for posting your request on History Hub!
In October 1974, the Army Standard Installation Division Personnel System (SIDPERS) included Personnel Data Cards (PDC) that replaced Morning Reports and Zero Strength Balance Reports (ZSBR) that replaced rosters. A SIDPERS contains information on the service member during the entire period of time assigned to an organization, regardless of length of time. It also includes information about TDY, AWOL, DEF, gains, losses, promotions, reductions. SIDPERS was discontinued on November 21, 1990. For a copy of a SIDPERS record, please complete a GSA Standard Form 180 and it mail to NARA's National Personnel Records Center (NPRC), Military Personnel Records, 1 Archives Drive, St. Louis, MO 63138-1002. Please include the individual's name, Social Security Number, complete organization and location, and the date the individual left the unit.
We searched the National Archives Catalog and located the series Organizational History Files, 1959 - 1973 in the Records of the U.S. Army, Pacific (Record Group 550) that includes file units titled Unit Histories: 155th Assault Helicopter Company and Unit Histories: 155th Aviation Company. We also located the After Action Reports, 1965 - 1972 in the Records of the U.S. Forces in Southeast Asia (Record Group 472) that includes a file unit titled Air Assaults/Assault Helicopter Companies. In addition, we located the series Aviation Unit Records, ca. 1965 - ca. 1973 in Record Group 472 that includes an Organizational History of the 155th Aviation Company for 1965 to 1971 in Box 628. For more information about these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org. We were unable to locate records of the unit after 1971.
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. We apologize for this inconvenience and appreciate your understanding and patience. Also, NPRC will continue servicing requests ONLY associated with medical treatments, burials, and homeless veterans seeking admittance to a homeless shelter. If your request is urgent, please see Emergency Requests and Deadlines. Please refrain from submitting non-emergency requests such as replacement medals, administrative corrections, or records research until NPRC returns to pre-COVID staffing levels. Please check archives.gov/veterans for updates to the NPRC operating hours and status. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful. Best of luck with your research!