i ordered in very late december and specifically asked for a german build. i got the van in, just as i spec'd it in late April. But i had bought cars from this merc dealer in the past and this might have helped.
My 2020 long wheel base arrived about 7 days ago at Coach House RV in Florida. They will build it to be a Class B RV. Completion date July. I ordered in Nov 2019. Not sure if Coach House placed the van order with MB prior to my down payment. VIN number lookup says built in Carolina, USA.
German build ordered November 30th. Scheduled delivery at the end of April and delayed until June. I was told the delay was mostly due to the van being in a long queue at a port in the UK waiting to cross to Halifax.
In Europe due to the new emissions engines and real world testing you cannot get your hands on a 4x4 until March 2021 at the earliest. The option to order is removed from the MB site but the factory is up and running now for a few weeks and orders prior to end of April are being fulfilled.