I am new here, and done quite a bit of research and feel I am ready to remove my injection pump, but just would like some feedback and people to steer me right. everything I have read so far is in regards to turbo diesels and newer cars, nothing around my application.

Background:
I have acquired a 1979 Mercedes 300D (non-turbo), it was in a guys barn I did some work for him and he traded the benz for the work.
I was told from the start no one knew what was wrong but the place he brought it before parking it in the barn told him the Injection pump needed to be rebuilt, he didn't want to do it, so he parked it. Well the shop he brought it to did 50% of the work removing all the lines off the pump oil filter etc, injectors, the whole jazz and left it, but they did cap the lines and empty holes so that's fine.

At this point I have decided since it nearly off, and the shop said the pump needs rebuilding I am just going to go ahead and do it. I have a close friend that has a rebuild shop and he will rebuild the pump or check it out for me no problem.

My question begins with how do I start? where do I begin? my concern is timing, the rest is just wrench turning.
I have done tractor injection pumps before and timing is just line up degrees BTDC and the tractor pumps I have done have a gear to line up with marks and timing window with marks.

This Mercedes process seems to be very similar. My confusion is I would like to use a Pump lock but have no way of determining if I can with my pump.

To start my block numbers behind IP read : 617 011 09 010? (the last looks to be 010)
The tag on the pump is definitely: RW 375/2200 MW 19

What can you tell me from these numbers and combo?

My procedure to start pump removal is going to be done by removing the oil filter housing. after that my concern is where should the engine timing be before removing the pump? (does it matter) is It really just 24 BTDC and just pull the pump and voila. lol

since I don't think I can use a pump lock,
My thoughts are, set the engine at 24 BTDC on the compression of #1.
I would leave timing there and then slide the IP out.

After I have received rebuilt pump, reinstalling would be set the timing marks up on the injection pump and then reinstall, assuming the engine has not turned. tighten it down, and then I can fine tune the rest after that.

What am I missing? besides minor details of removal with brackets etc. I am just curious if on these older pumps you just rip em out and set em up and put them back in?

Any tips or tricks to make the job easier? again new hear and would love feedback!

Or if you have a link to a thread where these questions were answered for my application that would be great!

Thanks in Advance!