I have a 1980 280E and 450SEL
The oil filter comes with two o-rings, washer, and a copper o-ring.
The large o-ring and washer are obvious to me, but the other two have me a
little worried since I don't know where they go.
Are they necessary or just extras for an application I don't have.

Any light shed would be appreciated.

p.s. I'm also in the process of setting my mix vis-a-vis fluke 83 III hooked up to a tap coming off of the O2 sensor. Target voltage 4.5 vdc using the averaging function on the meter. All adjustments done after getting the motor good and warmed up. Car was getting poor mileage, 12 mpg, when I bought it. Noticed the O2 sensor was disconnected but didn't give it much thought. Then read about checking the frequency valve with a duty cycle meter. readings were in the upper 80% duty, so I checked the O2 sensor. No voltage, so I replaced it. Engine started 'hunting', so I knew the circuit was now getting feedback. Havent checked the frequency valve again since getting the O2 sensor hooked to the fluke, but man the mileage sure has improved. I figure someone disconnected the faulty sensor and richened up the mix just so the car would run. She's a top, 117K miles with a 110 motor, noisy valvetrain, but 150 psi compression over all 6 cyl.
Not bad for a $500 car

As this filter is for many applications including 6 cyl & several V-8s so are the seals! Use the ones you need & discard the others as they are for other cars!
A 1980 car is a SMOG delight!

re:smog delight
 

the 280e has a smog pump and lambda control, but the 450sel doesn't?