Although SAV is the old product, it is still in use by many companies. There are many questions about the differences between SAV 10.1.x and SAV 10.2.x, migration from SAV 10.1.x to 10.2.x etc.
The main difference between those versions is that SAV 10.2.x additionally contains installation package for Windows Vista:
About Symantec AntiVirus 10.2 for Windows Vista http://www.symantec.com/business/support/index?page=content&id=TECH102012
The first release for Vista - SAV 10.2 - has been published when SAV 10.1.5.5000 for other systems was released. In reality, SAV 10.2 and SAV 10.1.5.5000 is the same version (when 10.2 was installed on other operating system, it was displayed as 10.1.5.5000).
Later, there were more releases of SAV 10.1.x and 10.2.x published at the same time. Similarly to 10.2 and 10.1.5.5000, they correspond to each other:
10.2 = 10.1.5.5000 10.2.1 = 10.1.6.6000 10.2.2 = 10.1.7.7000 10.2.3 = 10.1.8.8000 10.2.4 = 10.1.9.9000
So, if for example the version 10.2.3 was installed on non-Vista system, it will display 10.1.8.8000 version on the client interface.