Specifically from 1850 to 1855.
Dear Mr. Rusco,
Thank you for posting your request on History Hub!
If you are interested with records related to Native Americans at Fort Smith, Arkansas, we can recommend that you contacting the National Archives at Fort Worth, Texas. You can email the facility at: email@example.com. There is also a Native American Finding Aid online for microfilm for the Fort Worth Facility at: https://www.archives.gov/fort-worth/finding-aids/native-american-microfilm.html.
We hope this is helpful. Best of luck with your research!