On modern engines replacement is pretty much preferable today. This is an older fashioned engine. There are two smaller bolts in the timing chain cavity as well to remember to remove.

Personally I would remove the head and using a straightedge see how much warpage is present using feeler gauges. The best place to get the head done locally wherever you are is to ask a local Mercedes dealer that has been in business for years. Where they send their local auto machine work. Plus if they are happy with it. A good shop might even put it through their contact for you to avoid the off the street prices. Unfortunatly the world seldom acts like that anymore. It is a personality thing to try to get them to do so perhaps anyways. With no markup but buying all the people in the back shop perhaps a Kentucky fried dinner.

It may very well need a few valve guides replaced. I would ask for the original Mercedes rubber valve seals as well. As there was some discussion about the quality in comparison with the aftermarket ones. Do you have any ideal of just how long the better half ran the engine after it blew it's cool?

For some reason more automotive machine shops seem to have issues than in the past today. Yet technically their equipment should be better. As a result never use one that does not have a good reputation.

There is nothing really special about that head. Other than Mercedes asks for a smaller clearance when reaming the replacement valve guides if needed.

Inspect the first cam lobe as this was about the end of the era that they had improperly hardened cams towards the front. Also number all the cam followers. I assume you already know they have to go back in the same positions.

I also have wondered if the poor work that is too common today in many places. Was caused by the drop in their volumes of incoming work. I cannot remember a friend reciently that has sent his head in for example to one. Perhaps it is several factors.

I always checked the valve seal when I got a head back with a thin liquid. Before installing it. If you know the accurate miles on the car and mention it. Generally it gives some indication of what it will probably need. You have to trust someone in the auto machining business. Checking them out helps. It may have changed but in the past I found the better places seemed to charge less as well.

Before you remove the head. I may have mentioned before. Set the damper at zero with the cam marks in place. If the cam marks are 180 degrees off just rotate the crank one more time a full 360 back to the Top dead center at the indicator. They will be on then.