Turbo replacement help (OM617)

[83w126]

I had to replace the turbo on my 300SD, and its almost done, but it has been sitting in my driveway for over a month because I can't get the last bolt back in.
I posted about this before because I wanted to try replacing the part the bolt in question threads into, but the part is NLA, and I don't think that damaged threads are the problem anyway.
My dad was able to get the top bolt in since I took this picture, but neither us could get the bottom one in. I sometimes have trouble putting stuff like that back together because my fingers aren't very strong, but im not sure if its just me or I am doing something wrong. Should I just put it back together without that bolt? I would rather have it be right, so if it needs to be there to not eventually cause something to crack from vibration I would rather take it to a shop and pay the $500 it would probably cost to have it put back together properly, but that seems silly for just one little bolt.