I am looking for some insight on a set of leaf springs I have.

I have owned a few sets of C4ZA-5556-S leaf springs and they have always been 3 main leafs and the 4th small one with the engineering number, for a total of 4 leafs.

The set in question are the same C4ZA-5556-S with a date of 137, but they have a 5th leaf (the second longest one was added in the pack) the one added is the one with the square end.

My questions are:

Do these look factory?,

Did Ford offer a tow package option for a 65FB K code or Shelby where they would have possibly added a leaf with a tow package??

Did the Competition R models have the same 4 leaf pack as the standard Shelbys and K codes? or could the R models have had an added leaf as std equipment

thank you in advance