yes, I removed the pin. It is very precisely machined. What did I have to lose other than having to buy an other injector nozzle, that I thought I would have to do anyway. It seems that cleaning the gunk off of the end of the pin where it met the orifice seemed to fix the problem. I don't really know why this would necessarily be a bad thing as long as you were in a fairly controlled environment.

I believe the pin kind of seats in the one position over time. This would make a wear position inevitable since I believe it does not rotate.
As a calculated gamble if your idle is not as good as before the cleaning having that one injector checked out properly. Might be worth the money as nothing else has changed. A proper check of it involves very few pesos. Rather than disturbing the other injectors why not try running some cleaner through them. I think marvel mystery oil is worth a try as a purge.

It always idled a little rougher than I liked in gear. I think it actually idles a little better now - I may take them all out to have them tested - do you just take them to a diesel shop or what?

I'm also planning to do the drip timing and valve adj.

Mercedes does recommend they be checked at least every hundred thousand miles. The way I see it is if the idle is excellent and fuel milage is up with the best ones we hear of then I would leave them alone.
If there is nothing really wrong with them the check is pretty reasonable as well. If something is wrong it almost pays for itself in this area to repair the injector.
I would as a general rule ask around for the best injection shop in your area.