Couple of things to keep in mind here.
The GA Release of 10.2.300 was 10.2.300.2. The only way you would see 10.2.300.0 / 300.1 as the “Version” value in your Sysconfig is if you had an early access release and those versions (the software) are actually not compatible with the GA version or subsequent Updates.
Once you update a Client to work against a newer Update - 10.2.300.8 for example - that client is no longer valid to work against lower versions - 10.2.300.5 for example. It is expected that all AppServers referenced by the Client\Config*.Sysconfig files are at the same version and all of them match the Client (after it finishes the Auto-Update).