I was able to pull an injection pump off of a 1984 300D this morning. Fortunately, someone had already removed the oil cooler lines, so removing that back bolt wasn't too bad.
Because the pump is off of an '84, I can use this tool to time the pump:
Mercedes Diesel Engine Injection Pump Pin Timing Tool | eBay
Does anyone have a link to a good thread on timing the pump with this tool? From what I've read, this is a lock pin and you rotate the engine until you meet significant resistance. What you do after that, I have no idea.