Equipment question.

[rmneder]

I have a 1972 K10. It currently has a 4 inch lift. I want to go back to stock springs . For the front there are 2 leaf 900 lb spring and 3 leaf 1100 lb springs available. According to the 4X4 forum there is a standard spring and a heavy duty spring. My spid does not specifically call out heavy duty front springs so does that mean I originally had the standard front springs or could they be part of another equipment package? is there a difference in ride quality or height between the standard and heavy duty spring? Also I'm not overly concerned with how original my truck is so is one better than the other? Thanks.