I suspect EoQ push is prompting this. They have good certainty on their inventory of build materials and factory labor between now and the end of the month, so they know how many units they can produce and where they will be able to deliver them before April 1.
I got a similar text for a Model 3 at the end of last year ("DECEMBER" instead of "MARCH", of course), and they delivered my Model 3 during the final week of the year. As an aside, I asked at delivery (before paying/accepting) whether the delivery folks had seen any indications that my MXP would be available sooner than the then-estimated April 2022 date, and they said it was highly unlikely to arrive soon since they had only seen 2-3 refresh MXLR deliveries and 1-2 MXP deliveries at that point. Of course, then they called me two days later to ask if I could take delivery of an MXP they had in my configuration before close of business. They offered to take the M3 off my hands for ~$15k less than what I had paid two days earlier (including tax/title/license/etc.). I declined, and they drug their feet on registering it until this month, so I've had a 2022 M3 sitting in my garage for almost three months since Carvana/Carmax/etc. won't tender an offer until registration is complete. They still haven't managed to complete registration for the MX somehow.
Anyway, short story is that I'd put a decent amount of faith in their ability to deliver by the end of the month if you received a text. That said, I wouldn't put 100% faith in anything they say, and I certainly wouldn't begin making moves on the assumption that they'll deliver if it means you'll get burned when they don't. Maybe 80% chance they deliver by 3/31.
