I am not perfectly clear on this, but as I understand it, “Enhanced Autopilot”, often abbreviated as EAP but not to be confused with the “Early Access Program” also abbreviated as EAP, was a option package that predated FSD or perhaps existed alongside it for a while. I purchased my car in Sept 2018 from inventory, it was manufactured in Feb 2018, and I purchased the FSD option. I don’t recall whether EAP (Enhanced Autopilot) was one of my other options.
I also understand that somewhere along the line, Enhanced Autopilot as an option available for purchase disappeared, but remained attached to the cars purchased with that option. And that it includes most of the features released so far under the FSD umbrella, I think “Smart Summon” being an exception. As more FSD features get released, the big one being city AP, the gap should widen.
Am I anywhere close? I assume your car was purchased with EAP? Was FSD an option at that time?