A decree of adoption does not affect any right or benefit vested in the adoptee before the decree became final.
Mont. Code Ann. § 42-5-204
Rights of adoptee
Known as the Montana Adoption Act
The act spans §§ 42–42 (192 sections).
En
Official source: Montana Code Annotated (Montana Legislature). Reproduced from public-domain Montana statutes; confirm against the official source for the current text. Not legal advice.