The reference J# is for coins since 1871, but there are currently over three hundred references to J# for coins issued before 1871.
Kurt Jaeger wrote several other references for older German coins and the reference codes on pre-1871 coins are probably from those books. It would be useful for helpers with those references to update the reference codes.
I have Jaeg 2 FH and Jaeg 6 FHI so references from Baden, Frankfurt, Hessen-*, and Isenburg have been fixed.