If you mean whether you can just restore to iOS 7 and leave it as stock, yes you can. Note that if you upgrade to iOS 7.1 (latest), you cannot jailbreak it on that particular iOS. And the only blobs you can save are 7.1 blobs. You won't need them to restore at the moment because it's still being signed, and A5+ (iPad 2 and newer, iPhone 4S and newer, and the iPod Touch 5th Generation) devices do not have bootrom exploits so it's highly unlikely that they'll ever be used. You can save blobs using TinyUmbrella.
Here's a little tutorial on it if interested.
If you still want to downgrade to iOS 5, you can after upgrading to 7.1, but note that you'll be limited on AppStore apps as most require 6.0+ and a nice chunk of apps requires 7.0+ to run.