downgrading from testing to woody

[Nyc0n]

I normally run testing on both my machines, but I have been having some issues and wanted to try to go back down to stable or woody, when I upgraded to testing it took about 45 mins to download and install all the packages, via apt-get dist-upgrade, I changed my sources.list file back to woody and did an apt-get clean and when I did the dist-upgrade again it took literally 3 seconds and didn’t download anything and said it had completed, I know there is no way that it could be done that quick, so im sure im not running stable, is there a way to tell? Do I have to reinstall to get back to stable? What do I need to do?   nick