Took me about an hour of web searching but here is a work around. I dont know who the credit goes to but it works
Last update, I can use themes from LG Smartworld as well now, it just takes some convoluted steps!
Download the "launcherpro" app from the play store, you don't need the launcher itself, just its "Activities" widget.
Add the activities widget to your home screen it will give you a list of apps/functions of apps that you can add as a shortcut on your home screen.
If you scroll down to "Home" one of the options is "Theme" with the subtext "com.lge.launcher2.theme.LGThemeChooserActivit y". Choose that option and you'll get a shortcut on your home screen that lets you change the theme(You'll have to install some first the phone only comes with the one default theme). If you get a menu with no options make sure you have chosen the right Theme option(my phone had two different Theme listings but the subtext was different only one says LGThemeChooserActivity).