I've heard there is some confusion. The letter was only asking if people were interested in either model, not telling them they would be scheduled for one.
Here is the first email from Ford that was sent to me. I responded and asked for additional information regarding these two models. Ford's response was - information will be available at a future date.
:::In anticipation of the 2019 Model Year Ford GT, we are planning on offering two limited edition series: Heritage and Lightweight. Official details and pricing for each series will be available closer to the start of 2019 MY production. Production of both series will be available in limited quantities at a premium price.
You are receiving this communication because we expect your production date will fall in the 2019 model year timeframe, and would like to gauge your interest, if any, in these series so that we can plan ahead.
If you are interested in the ’68 Heritage or Lightweight Series, please simply reply to this email, noting your interest, by April 23, 2018. All 6003onses will be reviewed and selected owners will be notified by the Ford GT Concierge team.
Please note that selection to order either series will impact your timing in the build schedule.