Changed the header to better reflect the question.
Springs for a 67 would normally be marked where yours are
And thanks allot fo posting the stamped engineering number since (on rear spring application) just the make, model, year and other details don't always get us an match
With that said - those are the same springs and markings I've got documented on other similar 67 390 GT suspension cars Can't confirm an exact match (according to Ford) since things like body style, AC, trans and all that can affect the springs placed on the car but I really doubt that someone found a match this close and put it on your car as a replacement just by chance