If you’re correct (and your logic makes sense to me), that would give the assumption no one (matching the spec of the inventory cars) will be delayed in getting their cars this/next month.Purely speculation on my part but I'm thinking what's happened is this:
Tesla have manufactured a bunch of cars corresponding to the specs of outstanding orders, stuck them on a ship (most likely Grand Dahlia) and meanwhile people have cancelled or changed their orders (e.g. end-of-quarter push involved Tesla offering P- to people waiting for LRAWD, some may have bought from inventory when there were actually cars available in the UK - again from previously cancelled orders.)
Those cars still get put on the ship even though there's no order outstanding for them. If they just ship them to the UK, someone will inevitably buy them, but by putting them on the inventory page allows someone to place an order for them and if the car is sold en route to the UK it doesn't sit somewhere gathering dust and not earning Tesla any money.
Now, what about VINs for people with outstanding orders? I'm guessing those will be assigned soon, and there are likely cars on the ship that are due to be matched to orders. But that can happen at any point during transit - Tesla gain nothing from rushing to assign VINs, whereas rushing to list cars on the website could gain additional sales. Which is fine IMO, just so long as they don't prioritising inventory stock over orders!
So they've probably reserved the cars that correspond to oustanding orders and VIN numbers could pop up any time soon for them.
Less likely is that they could be making extra cars just for inventory, but there are so many people waiting that it would only make sense to do this if Tesla specifically want to make some extra sales whilst leaving a few more people waiting.
I also have no idea how long it takes between the factory being told what to make and shipping - e.g. up to what point after cancelling an order would the factory be able to avoid making the car?
I for one would be gutted if I’m not matched now, considering I saw 3 on there yesterday matching my spec.
Here’s hoping all outstanding orders are fulfilled on the next boat!