Take a photo of the boom and post. Also, if there is none, then look in your parts to see if there is a M shape hook and we can go from there. If none, go on line to U.S. Spars and see if you find it there. You have a Z spar mast and boom and Z spar left the U.S. for which I am not going to discuss why and renergized in this country as U. S. Spars.
However, if you want to, an alternative is to attach an eye below the boom and a cleat on the opposite side. Then take a line and attach at the eye pad and thread it thru the reef point with the sail fully deployed and long enough to tie at the cleat on the other side hanging loose to avoid a short line which you would have to put thru the reef point everytime. It would be a little easier this way. I have also arranged for single line reefing but entails more work and blocks.