Yes. Bucket seat cars only have seat belts for two passengers in the front; Bench seat cars have seat belts for three passengers. As for technical stuff I don't know. Be aware that for 1970, 1971, and 1972, each year has its own design buckle. 1970 has all buckles for seat and shoulder belts the same size. 1971 has smaller buckles and latches for the shoulder belts. 1972 has shoulder belts that attach to the seatbelt latch before it seats into the single buckle.
