A full restoration could be a 120 to 160 hour bill. I just spent about 3 hours on just the bracket etc in the photo.
Option 3 would be a sympathetic refurbishment. There are a few things there that are incorrect and a few things that could use some help. Doing that would both preserve the original feel and spiff it up a bit.
Here is a what I would do.
New battery hold down and cables. Mercedes factory battery.
Remove black covers from subframe mounts (below brake master). They are not correct on a 280. Replace washer bottle, cap and lines, all hose clamps (Kits available from Authentic Classics etc.) all cooling hoses and fuel lines.
Paint power steering reservoir cover, coolant overflow tank and air cleaner cover.
Replate all the upper parts. Throttle linkages, wing nut on power steering reservoir, injection lines and the plate where the black emission relays are mounted. These are all yellow zinc or yellow cadmium. Bright zinc plate the clamps for the coolant overflow tank, the clamp that holds the power steering reservoir to the bracket and the oil filler cap.
I think if you did that you would be happier when you open the hood but could still call it “Original”.