yes you can restore it.
I allways shut down the Netbackup Server first and in my case I make a tar ball of the /usr/openv file system and put in in a safe place, then I install the MP4 on the Master.
Sometimes if I have space I will make a copy of openv and soft link it to the copy and upgrade the copy and "not" the production system.
Best to mess up the copy and not the production, if it works then delete the copy, make one more and upgrade the porduction.
cool?
J