I doubt it is out of stock everywhere because my dealer reached out to me this week to schedule a mobile tech to replace mine, theyre coming out tomorrow.
Where did you see that? I found this tweet from Rivian that sometime in march they'll see chargers in the car and only after that will they start sending out adapters.
I saw a post on Reddit that said he found it in connected services and that he couldnt reserve it yet. I tried and got #30 so I'd be willing to bet that was the first report.