What's the difference between USA Limited Edition albums on BAEKHYUN STORE and albums on other sites?

USA Limited Edition Albums are only available for pre-order at BAEKHYUN STORE and nowhere else. All physical albums on BAEKHYUN STORE, except for the Hello, World (Photobook Ver.), have USA Exclusive package content. All digital albums are available for pre-order exclusively at BAEKHYUN STORE.

What's the difference between Hello, World (Signed Cover) and [Signed] Hello, World?

I already purchased Hello, World (Jewel Ver.) USA Limited Edition or Hello, World (Photobook Ver.), but I want to buy the [Signed] Album version. Should I cancel my previous order?

I ordered Hello, World (Jewel Ver.) USA Limited Edition or Hello, World (Photobook Ver.) before the [With Photocard] version announcement. Will I get the Special Photocard?