Q: I erased it using Find My Mac, but forgot to sign-out of...

I'm selling a Macbook Pro 13.3" Retina, SSD, mid 2014.

I want to to reset it, to an out of box state. So, I backed-up my hard drive to a WD MyPassport external hard drive using the TimeMachine app, and then I erased it using Find My Mac. I didn't remove it from my list of devices, sign-out of iCloud and remove data, or  iTunes data, and I didn't unauthorise the laptop first.

After the erase was complete, I entered my 4 digit code to unlock it, and realized that I was doing it all wrong. In this state it is to this point, the new user/buyer could use his AppleID, download/reinstall the OS X software, and follow the prompts in the setup guide.

In order to reset it, to an out of box state, before selling it I have to login w my Apple ID, download/reinstall the OS X software, and follow the steps in this guide:

What to do before selling or giving away your Mac

Or, do I...?

I have a total of 4 Macs authorized with my AppleID, including this one.