Forgot to turn off Find My Mac

I erased my hard drive on a 15" Macbook Pro Retina in preparation for selling it to Gazelle. I forgot I was supposed to turn off Find My Mac. I did sign into iCloud online & remove the device from the list of my devices. The device boots up to the setup screen at this point. Is this enough to turn off Find My Mac? I'd prefer not to have to reset the Mac up again to turn off Find My Mac only to have to turn around & erase it again. I know that there can be a delay at Gazelle when you sell them something with Find My Mac turned on; but I believe I have performed the remedy by singing into iCloud & removing the device there. The only thing that confuses me is that iCloud reports that if the device goes online again, it will reappear in my list of devices ... which it should not. (This may just be a warning for devices not erased after being lost, etc. That is not the case with the MacBook I'm selling, of course.)

Can anyone confirm that I've done what I should and that things will be OK? (I called Gazelle; but the tech person I spoke with didn't seem to understand the question. She gave me a link to verify the activation status of an iPhone.)

Thanks,

Robb