1967S - 305142 built July 1966 - Factory Press/Literature car located in France

[911T1971]

Greg, noted.
The inertia belts look odd and as another member sugested, it looks first like a crude update.
Since reading the infos about your 911S barn find, one wonders if the inertia belt not got mounted by the factory.
If they went testing the cars, who cares about looks. You might contact the french restaurer of 305142 if he kept the belts because always in the car. They look similar to the one in 305142.

I agree that both cars might got an overhaul before get sold to the public or given to some dealer/distributor.
If you read the story of the 7 prototypes (13xxx) in Tobias Aichele's book "911 forever", one can see that they received multiple updates (interiors) and/or engine swaps, until either got scrapped or to be sold.