Rare 73 Dart Sport, Moon Roof, A/C, #49

Yeah its definitely an interesting car. Whats Interesting and Ive never seen before is that all the seams in the jams and the spotwelds in the engine bay were leaded smooth. I asked the owner(Hes had the car since 1974) about it and he says thats the way the car has always been. I thought that maybe it was done during a repaint but it wasn't. Why would mama dodge spend this much time on this car? Anyone else have their car done up this way from the factory?