Lock question
 

I need to get into the trunk of my 1976 300D. The key that I have is a worn copy of a copy of a worn copy (you get the idea) and does not work in the trunk. I have seen the interior twice, once when we purchased the vehicle, and once not to long ago. Is there any way to get the original key code for the vehicle in hopes that that may work?

Unfortunately I have this bad feeling it's not your key.
Look at my thread through search "300SD Trunk Lock Failure" If you have questions PM me

If you remove the First Aid tray, you can open the trunk with a long stiff wire after popping off the black plastic lock cover on the rear closing panel.

Looking at another cars lock will show you what you need to do to pop the trunk lid.

You need to put a shop drop light in the trunk to see what your doing...a flash light won't work.

On the SD(126) there is about 3" to work with below the First Aid Kit, don't think the 117 has one. The plastic black bolster on the lip of the trunk has to be pushed forward off it catch points and then pulled back - but the two latching points are going to keep you from pulling the carpeting away from the inside trunk frame. Thumbnail 1 is looking down on two latch points #2 is ouside wall of rear of trunk.

What is the First Aid kit and where is it located on the vehicle?

The 115 does not have a First Aid kit. If your vacuum works on the trunk, don't lock it after you have it open.

Good luck,
Jack

If, as your original post suggests, you need a new key, the dealership can order you a brand new (and very sharp) key based on your VIN. You'll need to present the car registration showing ownership and some form of ID. Should be approx $25 and take a few days.