Pues parece ser según una respuesta recibida a un usuario en reddit que tras el sorteo tienen en cuenta para el envío del correo el orden cronológico de reserva.
Message from Steam Support on Jul3@
hours ago
?4:37pm|4
User's who secured reservations after
the randomization have units in the current
production run. Steam support does not have a
breakdown of the production run and we're
unable to provide individual timelines or
communicate your current position in the
reservation queue. We can share that all
reservations will be fulfilled in the order they
were originally placed.
When your Steam Machine becomes available
for shipment, we will send you another email
with the option to purchase. You will then have 3
days to complete the purchase before we cancel
your reservation and move on to the next person
on the queue.
I understand your excitement, but Steam support
does not have any further information on wait
time estimates for the reservation queue.
Steam Support