The seatbelts intended by the manufacturer for use in a sedan should be used in a sedan.
The author took the seatbelts from a sedan and tried to use them in his truck. The latch seatbelts did not fit, and the seatbelts did not work.
The wrong conclusion: The seatbelts are not recommended.
The right conclusion: The seatbelts should be used as intended by the manufacturer.
The useful information from the test: Those seatbelts are not universal (which was expected because the manufacturer did not mention universality in the instructions). However, it does not hurt to check whether the manufacturer tells the truth.