Men were recruited in multiple cohorts over the course of several years, and the records of different cohorts were maintained in different ways by different administrative structures.

Some men who trained in the program may have been deployed in roles that were not clearly coded as Code Talker assignments in all administrative records.

Some men died in combat before complete records of their specific role were finalized.

The uncertainty is not large — the range of 375 to 420 is relatively narrow, and the general scale of the program is well established.

But claiming a single precise number overstates the confidence that the historical record actually supports.

Responsible historical accounting acknowledges the uncertainty while still conveying the scale: several hundred Navajo men, across multiple years and multiple campaigns, made the Code Talker program work.