I havent looked at the numbers but it sounds about right. You have to keep in mind that for Tesla, with no dealership network, all cars are either in their inventory or sold. They cannot "sell" the cars to dealers and have them sitting on lots (basically an inventory transfer).
As for the gist of the question, 45K or 50K of that came from this quarter. This is why the inventory on hand jumped. If we divide 1.8 million by 365 we get about 5K cars per day. The inventory this quarter jumped from 16 days to 30, that is why I think your numbers sound correct.
Where are those vehicles? Many of them are in transit with some sitting in the Tesla owned showrooms. This quarter was odd with a supply chain disruption (Red Sea) in the middle of the quarter.
We will see how this unfolds after next quarter, if things even out. When supply chains are disrupted, and then resume, with only a few weeks left, a lot of time the inventory simply isnt in the right place.
For example, we have the China numbers for March for Tesla, 90K. But we have no idea, as of yet, how many were sold in China verses exported. Whatever is exported is still in inventory since a car is not sold under these circumstances until the owner takes delivery.