This does sound odd. It is not physically possible to have shackles at both ends of the spring. One of the ends would fold over, and rest on the frame, or worse yet, against a frame rivet, putting extra force on the shackle, enough so to snap bolts.

You can lower the front mounting , and use the longer shackles both to get more lift. But the front normally remains a solid mounting point.

This picture shows someones modification to make a lowered and adjustable front mounting channel. You can see the pivoting shackle to the rear.

NOTE: your rear shackle should have the top bolt running through the frame, not as shown in this picture. This is something that was cobbled together.