Hi & welcome to the forum.
Our friends in the States may well have some information that could help you, but I can tell you that the first few TR7s imported to the USA were a batch of 35 fixed head cars for the dealer press launch of the vehicle in January 1975.
According to David Knowles excellent book TR7 The Untold Story, the quality of this first batch was so poor that the whole lot were stripped down by the Group 44 team & then the good parts were put back together to end up with 17 cars that were good enough to present to the press & dealers!
There were no convertables as these were not in production until 1979.
I don't think there were any rally prepared cars in that first batch either, although of course the car did have some success in motorsport in the USA later on.
Tony
<font size="1">1981 2L FHC Cavalry Blue - very original & not rusty!
1980 3.5L V8 DHC Regency Red - on the road again.</font id="size1">