Can anybody narrow down the year of this First Generation Ford Bronco?
http://www.youtube.com/watch?v=gW2iAb-WtIo

That's a good question. It's at least a '69 because of the high-mounted side marker lights. I've wondered about how to ID the years other than this.

Also what year did the rear fender change to be like the front one? In the video you posted the rear fender is lower than the front. But many times it appears like this:
http://imcdb.org/vehicle_7019-Ford-Bronco-1970.html

When did it change from this?
http://imcdb.org/vehicle_502045-Ford-Bronco-1970.html

I'm going to have to ask an expert on ebay who sells old Broncos about the years sometime.

From what I could tell, the first pic is an altered Bronco. They refer to this style as being "cut" with the replaced wheel arches. The "uncut" ones are the way they were sold originally, like the second pic.

http://www.broncofix.com/glove/buying.htm