Just skimming over Woywod/Smith's commentary on the 1917 CIC (too much to reproduce or quote here), it looks like declarations of nullity could indeed be had at the diocesan level (no. 1866-1899 re canons 1960-1992), IOW, apparently not all annulments had to be signed off on by Rome. Again, I am just skimming, there's a lot there. Can anyone help me out?