Dell Kace agent is a 32 bit application. Hence on a 64 Bit OS, registry path HKLM in Dell Kace agent will point to HKLM\Software\Wow6432.

Hence, In Custom Inventory Rule, to access HKLM\Software of the 64 bit hive, use HKLM64\Software.

Ex: 

On a 64 Bit OS, to check the existence of a registry key from HKLM\Software\Intel construct Custom Inventory Rule as

RegistryKeyExists(HKLM64\Software\Intel)