I took pictures for you as I just followed the same process for my 751.
https://uploads.tapatalk-cdn.com/201...f859d6fbc8.jpg
I drove out the roll pin which secured the end plate.
https://uploads.tapatalk-cdn.com/201...3d1f7a1f4a.jpg
I then drove out the hinge pin.
https://uploads.tapatalk-cdn.com/201...6b61102e37.jpg
I used a replacement stock hinge pin from JDI (doesn't have a hole in the center), but you could probably re-use the original. You won't need the cup spring that comes in the kit.
http://www.shop.jdifirearms.com/Fold...1-34555071.htm
https://uploads.tapatalk-cdn.com/201...e4afe47daa.jpg
https://uploads.tapatalk-cdn.com/201...7812b387b7.jpg
I used a 1/8" diameter roll pin (sourced from a Brownells kit) to secure the stock hinge pin. The original roll pin that secured (and went through the center of) the end plate was too small.
http://www.brownells.com/gunsmith-to...t-prod553.aspx
https://uploads.tapatalk-cdn.com/201...d095c69c1b.jpg
I inserted the roll pin from the inside of the stock adapter.
https://uploads.tapatalk-cdn.com/201...9ac9453b04.jpg
https://uploads.tapatalk-cdn.com/201...db5a0facc9.jpg
I tapped it in until it seated against the indentation in the stock hinge pin.
https://uploads.tapatalk-cdn.com/201...97916020a0.jpg
The adapter swings freely and the stock pin is secure. Done!