Supposedly You can. I don't rename mine anymore.

Don't use spaces or odd characters ...I add info prior to the date leaving that intact.

 

You should be able to as long as you rename the folder, only (don't rename the img files), and you stick with normal characters, and don't use any spaces. If you want to try, just make a nandroid backup, rename it, then try to restore it. It will fail right away if there's a problem, and you won't lose anything.

EDIT: Beat me to it .

 

Also, if it is named BCDRS-20110115-0153 like my Amon backups are, then i just keep the file name and add something to it. That way you can always delete what you put and go back in case you need to. Like i named that one
"BCDRS-20110115-0153myn_rls4_1.14.2011"

 

I am using the current version of amon ra (atm 2.2.1), and have renamed all of my backups. never had a problem restoring them. i have used periods, underscores, and a plus sign with no problems. definately no spaces