One thing when you are looking for a 1/1 car to measure and photograph......the owner must allow you to touch, climb all over and at times tape materials to the subject to get shapes and profiles correct. So at times, owners of really valuable vehicles, have a no touch rule......the 1/1 must also be convenient or near other subjects you can study too. I have no first hand info on the S&H car....but this is how it was years ago when I helped out with a few vehicles. 3 model cars in the RM line all lived within a mile of each other in NC......3 got to help with. So it can be a combination of 'whys'.
Okey Spalding has them from time to time.....also ebay etc. All 1/25 scale AMX's or Javelin AMX'S (71-74) were tooled by JoHan and sold by AMT and JoHan. We need a new tool Javelin that could spawn all the Javelin and AMX versions.