Can you go back to iOS 6 ?

This may sound like a stupid question but I've never used the iOS betas before. I currently have an iPhone 4 running the latest version of iOS 6. I'm not registered as a developer so I'd be using a IPSW file downloaded from another sight to install iOS 7 beta 1.

After doing this, is it still possible to downgrade to iOS 6 by doing a full restore on my device ?