DATE- Norinco came into being in 1980. Your rifle is no older than 1980. Earlier rifles, made at arsenal /26\ can be dated by adding digits to 56. Other arsenals, no. Most of those can be ROUGHLY dated by production features only- long tang, short tang, pinned barrel (in order oldest to newest)
Once again your rifle is PRE BAN. Importation of these STOPPED before the ban went into effect. All Chinese SKS were imported BEFORE the ban.