They are all hand built made between 5/21 and 6/17/66, if the production data is accurate Fisher delivered them in batches of 2 to as many as 5 on any one day to Norwood, where they would be finished off and then sent to their final destination. Some remained at the plant, documentation says 12 were to be delivered to "manufacturing". Maybe all 12 of those remained at Norwood for testing, maybe some of them went to some other manufacturing location, whatever locations that would be part of the manufacturing organization that wasn't either Norwood or LOS. The last tubs were delivered on 6/16 from Plant no. 21, and the latest date that they were required at their final destination (proving ground, sales, tech centers, etc.) was noted as 8/1/66. giving the assembly plants about 4 or 5 weeks to work the bugs out and get them ready to go.
17 of them were sent to the proving grounds, only 1 (DD64) was noted as being sent to Chevrolet Norwood, 1 (DD63) was sent to Chevrolet Los Angeles, 3 DD29, DD54, and DD58, went to Janesville (figure that one out) all delivered to Janesville on 8/8. A bunch (11) went to the Flint manufacturing, 2 went to Oshawa Canada, another couple went to Atlanta, and the rest seem to be distributed amongst the various tech centers and engineering groups. So if any remained at Norwood for pre production testing after the intiail buildout was complete it would seem like it was only DD64.