How many leafs are in the rear spring pack, seven or nine? If less, someone either removed leafs from the pack or installed 1965/67 F100 5 or 6 leaf rear springs (a bolt on replacement).

Coilovers were available at the parts counter. If the shocks are marked Rotunda (as original), Auto-Lite or Motorcraft (service part replacements), they are genuine Ford parts.

Coilovers (usually Monroe's) were also available from autoparts stores, spring and front end shops, RV dealers.