Wait...hold on....unless they're there and I can't see them, I strongly recommend getting a set of stabilizer bars for the 2 lower 3pt arms. Without them, every time you make a turn your mower will swing to one side of another. It's one of my big personal annoyances hearing a mower or other implement bang around whenever I turn. 

It can be hard on the 3pt system, and can cause damage, depending on the implement being used. Some implements, like a plow, work better without the bars, though. 

One of the big reasons I love my 8N for 3pt work...it's a perfect factory system whose performance is hard to match with aftermarket kits.

This is a random internet search example of what stabilizer bars look like on an N. They are the long, flat stock pieces on the outsides of the 3pt arms. 

There are different designs, some use telescoping arms with pins (I like those better than the Ford design, actually), and some tractors (like the small Jap jobs) use turnbuckles (I think those are a sloppy mess). A quick Google search on 3pt hitch stabilizer bars should fill you in on anything you wish to know.