I just bought a used 62D2 for my 2520 and it came with the mechanical lift parts. I installed the lift, the deck, and was done in 3 hours. I took my time, and looked thru google images to find pics of the mechanical lift that I could zoom in on to see how and where the brackets went. It was super simple, but I know the 2320 mount is different. I was nervous installing it, so I went super slow and cautious. If you had a book or install guide, you could be done in a hour or so if you wanted to hurry. I just wanted to make sure I had everything right! I spent a lot of the time looking at pics online, so it took extra time, but in the end it works perfect and I'm soooo glad I bought it!
I bought a 2013 62D2 with about 5-10 hours on it for $1,300 including ALL the mechanical lift!

My 2520 mows like crazy with it, but the JD blades are not the best. They have little lift, so they let stuff behind and the discharge plugs in really tall damp grass. I have Gator blades to try next!