tbird II,
You missed the discussions on that on the BON. The first 25 cars belonged to Ford Motor Company (exec cars) & could be any color except NM. The Neimans start with #'s 0025 thru 0225. Jodrod has been able to account for both the first and the last NM on the data site.
They may or may not have been built sequentially as near as we can figure but were built in batch's of 10 NM's along with the other colors over a period of 2 to 3 months. From what we could gather at the time, they really didn't start on the NM's until late June or mid July - after they had more practice in putting these Thunderbirds thru the production line. Wixompooh might be able to fill in more details on them coming thru the paint dept.