i"m not sure what the newest thing is with the Eaz left system but if what you have allows you to tilt the hitchhead forward and backward then it's working OK. No REASON it can't be a threaded bolt but all the ones I've used were washers. The only down side to using the Eaz lift is that you'll need a couple of friction bars to control sway and they're not the MOST efficient means of doing it. There IS one other item to check into. Beside preperly being adjusted it FIRST must be the correct SIZE (spring bar strength). they SHOULD be sized for 15% of your trailers GVWR (as close as possible to that strength without being less than that number).
Good luck / Skip