Looking for an odd part for my 1/4 elliptic spring

Need the small removeable clamp, goes way in back by the shackle pin. Is this
something commonly available if you know where to look, or does anyone have a
broken 1/4 elliptic spring that still has this part? Other than this the
spring seems fine. I have the plate the bolts pass through, just need the "C"
part.
Dan