It usually appears in the source code of the webpage before it appears on any documents. It should be noted that if you do have a VIN in the source code that it doesn't guarantee itwill stay there! It can change or be removed completely but most times it remains the same.
How to check Source code
- Login to your Tesla Account
- Click "Manage"
- when that page loads, right click and choose "View Source"
- Hold CTRL and press F to search the page.
- Type 5YJ
- If you get a result then thats the VIN number that has been allocated to your account.
Interestingly some of the people that recieved cars last week didn't have a VIN in the view source, so its not a solid method, but can give an idication of some movement on your account.