This SO thread describes a simple way to automate the creation of a Keystore for signing apps.
echo y | keytool -genkeypair -dname "cn=Another, ou=MyUnit, o=MyCompany, c=US" -alias MyApp -keypass kpi135 -keystore /my.keystore -storepass ab987c -validity 9999
This works perfectly. From my understanding it is not possible to simply recreate the same keystore. I tried doing this by executing the above command twice, albeit with different names and then doing a binary file comparison. Sure enough the two files were not the same.
However, this is purely an empirical result. Am I write in thinking that once you have generated a keystore to sign and release an Android app you hold on to it for dear life since it cannot ever be recreated which then stops the app from being updated?