The numbers refer to the last verified Roundtails. More.
1966 - 1967 1600 Spider Duetto LHD
660001 - 665961
1966 - 1967 1600 Spider Duetto RHD
710001 - 710380
1967 - 1969 1750 Spider Veloce European version LHD
1410001 - 1412786
1969 - 1969 1750 Spider Veloce European version RHD
1470001 - 1470601
1969 - 1970 1750 Spider Veloce US version LHD
1480001 - 1482215
1969 - 1970 1300 Junior LHD
1670001 - 1672677
1968 - 1970 1300 Junior RHD
1695001 - 1690266
I have used a picture or report from Centro Documentazione to state the last of each version. The 1750 Spider Veloce used the same VIN, i.e. 141xxxx or 148xxxx for the Kamm-tails which may be confusing. Furthermore, most of the 1300 Juniors are no longer running for some reason. Very few of them are still alive.