I have modded C5's default theme and I would like to know if I can simply copy the theme and then rename it so I don't lose any of my customization?

I would like to:
1. Copy the default theme to the appropriate location in the C5 directory structure.
2. Rename the files necessary to make the theme different
3. Install it.
4. Then switch the the newly created/copied theme.

Is this possible? If so is is just a matter of renaming the description file and png file and the folder the files are stored in?

Thanks in advance for the help.