It should do yes, I just used it to pull down my old site that was about 2/3 years old out of date and I'd not updated it for fear of breaking it. Admittedly, I only pulled it down one way I didn't restore to an old WP version but it should still work. It cloned my site perfectly (100%) but I transferred it to a brand new install of 3.5 so I can't say for sure if it'll work.
It gave me no hint of any error at any time on my old 3.2 I think it was I'm not sure as I've moved it all over to the new one now. Seems very stable to me considering I tried almost every single other free plugin and they all failed, every single one but WP Clone.
The only error I found in any way was for an unknown reason. This plugin uses a server to server transfer process which failed after succeeding the first time. It worked to clone the old site but wouldn't reinstall on the new one with the transfer. I just uploaded the .zip file instead which works :)