There is many ways to find weblogic version installed on your system, exactly there is 3 ways to find tour Oracle Weblogic Version. lets show you how i did in my case case using my Linux Server . teh same principle should also work in Windows Servers :
WAY1
Using the registry.xml file located in your MW_HOME directory. or just find the file registry.xml
#locate registry.xml /opt/oracle/middleware/domain-registry.xml /opt/oracle/middleware/registry.xml /opt/oracle/middleware/patch_wls1036/registry/patch-registry.xml
Open The file registry.xml
#cat /opt/oracle/middleware/registry.xml
you can see ann info about the versio and the install directory
<component name=”WebLogic Server” version=”10.3.6.0″ InstallDir=””/opt/oracle/middleware/wlserver_10.3″″>
WAY2:
Using the .product.properties file located in your WLS_HOME directory.
in Linux Find it with locate product.properties
#locate product.properties /opt/oracle/middleware/oracle_common/.product.properties /opt/oracle/middleware/wlserver_10.3/.product.properties
Open the file .product.properties
#cat /opt/oracle/middleware/wlserver_10.3/.product.properties
Fine a line similar to:
WLS_PRODUCT_VERSION=10.3.6.0
Way3
Using the Oracle Weblogic Server Administration Console
Use the left hand menu to navigate to Environment -> Servers > AdminServer(admin) . Then, click the [Monitoring] tab. You should see a screen similar to the one below:
Enjoy