Efi not locked but might be if it connects?

I've spent days on this forum trying to figure this out.. It's not efi locked, but I got it in a trade and I'm questioning the persons actually ownership of it now after hearing certain things. It would've came from a place not a person, so Idk how they do I cloud.. Or if it was even theres I'm thinking worst case I'm out about 600$~ give or take.

It has my HD from my late 08 mbp Icloud and all 1tb El capitan.
I'm just curious what if anything needs to be altered for that first time it goes online. I pulled the airport immediately and bought a new one assuming it'll give me a new Mac permanently but I honestly don't know.. Any suggestions?

Thank you!