The earlier pattern was that there would be an oral exam before a judge, stemming from pre-Revolutionary practice. This article discusses the history of admission to the bar in Nebraska. When Nebraska first became a territory there was no educational requirement, and the courts just followed practice in deciding, in 1855.
The article then says
By 1867, a system for bar admission had developed. The legislature
believed it had the power to regulate the process. It had decreed that
each district court judge could admit bar applicants to all other
lower courts, and the practice was to admit such district court
lawyers to the supreme court on formal motion. Each judge was to
supervise a test of the applicant's legal knowledge, and each applicant
was to have studied for two years in the office of a practicing
attorney. If the applicant had been admitted to practice in another
jurisdiction, he was exempted from these requirements.
So the procedure was a formal motion, which may be in available records.