SDCL § 18-4-27: Prior instruments governed by prior law.

The legality of the execution, acknowledgment, proof, form, or record of any conveyance or other instrument made before July 1, 1939, executed, acknowledged, proved, or recorded is not affected by anything contained in this chapter, but depends for its validity and legality, except as to seals, upon the laws in force when the act was performed except as by other statutes expressly provided.