My 73 has the 3-point seatbelts. 73 was the first year for major changes to the 107 line. Power windows and 3-speed automatics were the other changes.

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73 450SL AMG "Millennium Falcon"
88 Volvo 740GLE B230F/M47
84 300SD Turbo (Sold, looking for new one)
86 300E (FOR SALE)
78 450SL (totalled by girl on drugs in SUV)
87 Volvo 740GLE wagon (totalled by Ford Expedition)