Some of the Aiming Rifle rounds also had percussion primers!
The Nordenfelt cases were frequently unheadstamped, but when they did have a headstamp, the British-made ones usually included the date, and the Woolwich Arsenal mark of "R /|\ L" (although some of the Mk.VI rounds were made by Kynoch, and would have their mark on them). The Nordenfelt rounds were not used much by Britain after about 1902, as far as I know, (although apparently some of the private firms did produce this ammunition into the 1920s, for export contracts), whereas the 1" Aiming Rifle rounds were still in use in 1945 (or at least listed in official documents).
The Aiming Rifle cases were usually headstamped, but the only one that had the date included was the blackpowder-loaded Percussion Mk.1, which was made in between 1897 and 1909, although the only dates I have seen on this type are 1898 and 1899.
Hope this helps.
Roger.