Many thanks to you, Amit, for this information and the scans of Chitor's dams.
Few mughal mints seem to have never use the new Ilahi era on their copper issues and coins are from others are known with Ilahi dates and AH >999 (Bairata or Dogaon for ex.).
I have recorded at least 9 mints with AH dates > 999 (some of them are very scarce indeed).
To answer to Abhinumis, according to Ajmer mint, it seems that the earliest date on a dam from this mint is 970 AH.