Prices paid for guns of this grade are determined by gauge, barrel and choke combinations, rib type, stock specifications and engraving. Expert appraisal is recommended. It is best to secure a factory letter from Cody Firearms Museum. With respect to such a letter, it is important to note that these records are incomplete and may be inaccurate in a few cases. Records for Model 21s built during 1930s may be missing. Special-order guns may have incomplete records. In such cases, a written appraisal from an authoritative collector or dealer may be helpful.