Yeah you definitely want the mounts that are meant for this cab. It's a fickle beast, it doesn't like any frames on it's monitor, and uses just the 2 pieces to mount directly to the cab. Once you're able to find a set, you have to remove the tube from the frame, be careful with this since it will be just glass, nothing really to grab onto. Then attach those the top and bottom mounting pieces to connect to the cab.
Hopefully you're able to source those mounting parts.
I for one am not messing with this monitor for a long time. It's set to vertical right now, and I don't really have any interest in putting back to horizontal. Especially since there is no real frame on it, there is a risk of breaking the neck if mishandled.
btw, thanks for the kind words. I love this cab, ever since I was at Neon Retro Fest in Florida a few years ago, they had 3 Windy's to play on and I was hooked. Got lucky finding this cab locally for a really good price, considering it's condition too. I put in a lot of work to make this baby shine!