Hello Ron,
Yes the 280SEL 4.5 is the donor car for these parts. In addition, many other misc parts are also usable. Things like the steering wheel, window cranks, steering gear box, tools, wheel covers, horn pad, rear brake calipers, side marker lights, many suspension parts, some dash switches, knobs cigg. lighter, are the same. The heater controls are slightly different looking but work fine in a W113 if needed. Since the 4.5 is a V-8 engine so very little engine parts are usable. However the electric fuel pump will also work fine but is a later configuration.
Joe Alexander
Blacklick, Ohio
