Yeah, unfortunately the hinge was discontinued long ago as well, and I'm guessing finding a new one will be about as common as finding an extension on the used market lol I'd assume I'd find a whole lathe like yours with both before I'd find just the hinge and/or extension. Wouldn't complain if I did, though 😆
Mine came with the outboard tool post, and I've not used it yet, but I do like to turn bowls (that's probably 90% of what I turn on the lathe anymore), so I'm hoping to use it more. I've got a Jet 1221vs lathe as well which has an extension on it. My plan is that if this new extension does indeed work with my Nova like the support person said it would, then I'll be selling off the Jet and going down to the one lathe instead of having two. Trying to minimize the duplicates to gain a little more space (looking at you island of 4 table saws)