Hello,
I'm afraid Kickstart and Workbench v1.3 are considerably less useful than the more recent v3.1 release.
I would recommend purchasing Amiga Forever in order to gain access to a fantastic Amiga resource, which will also allow you to use other Workbench distributions, including AIAB and AmiKit.
However, if you truly do already own a Kickstart v3.1 A1200, spend a few searching and you will quickly find the necessary files online.
Take care,
James
x