I was suspicious too, hence the initial post.
The screenshotted email came from [email protected], which seemed like a scam email address until I got an email from the second dealer I've reserved with a similar email address convention.
Like you, I also...
Couldn't figure out how to switch dealers for my existing reservation, so I canceled it and just created a new reservation with a different dealer. If they're asking for more money now, I'd hate to know how much more they're going to ask for when it's time to purchase.