I'm not sure what "ready" for production means. Could it use improvements? Of course. But doesn't that apply to every vehicle and probably moreso for every non-Tesla vehicle?
To answer the question I would pose this question: If I had one of the founder X vehicles would I think it's not "ready" for others, if it rolled off the line just like mine? I highly doubt it.
Well, first off, if it was "ready" we'd be seeing cars coming off the line. The final car would be (to borrow a chip fab phrase) "tapped out". I know that Tesla is constantly refining it's production process, constantly changing how the cars are made, but at some point the car was "done" and ready to be mass produced. I don't see any indication this is remotely close to happening with the X. The car doesn't seem to be "tapped out".