Those paint marks indicate std 3 door(cossie) springs, some of these despite what ford say were also fitted onto xr4i.
I've used the ahmed spring combo, and it is very good, personally I prefer AVO/chassis dynamics std ride height ones for the cossie.
You can find the rate easily with some bathroom scales, put spring on vertically, take a ruler to side, scribe mark at 0 load and another at 1" compression, then apply a known load such as weights till you get the 1" mark lined up, see what weight you have.

tabetha