There can indeed be a difference between being walked out on the spot, just as you've been notified; and actually being no longer employed.
It can be hard to tell the difference emotionally as you carry your box of stuff out to your car, though.
I was walked out.
In a previous job, two positions were consolidated into one, and I got it. The previous occupant of the other stayed to help me come up to speed, and clearly hated every day of it. Now *that* is what I call professional courtesy. When I later left that company, I gave 2 weeks notice, and worked to the last day, past the last hour, and missed my 'going away' lunch, too boot. Now *that* is what I call silly.