When iOS 7 is released to the public, will I be able to activate my iPhone 4?

I was trying to downgrade to 6.1.3 and iTunes went to verifying with Apple, then I got the activation error. I was wondering if I will be able to activate after Apple releases iOS 7 to the public.

No, you're stuck deactivated on the beta until you register your device's UDID with a developer account. The cheapest way to do this is through InstantUDID.com. It's $5, and then I was able to get past the activation screen on my 4S.