Dear Mark Flinspach,
Thank you for contacting History Hub.
Here is the portal for Vietnam War records research at the National Archives:
Additionally, here is a link to additional Vietnam War-era military records.
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. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful. Best of luck with your research.