If you are referring to the cross spring in the rear caliper that the retaining pins are held in place and keep the pads from rattling then ,YES. I think it keeps the pad retaining pins from falling out.
The rear brake disc is secured to the rear hub with an allen screw.
1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T