New engine for my G, but not sure what I bought.

Hi Everyone!

A new member here :)

A few years ago I bought a Mercedes Turbodiesel from a friend. He had done some research and told me it's a OM603 3,5, but not the one from the G (OM603D35A). But the mileage was unknown. So I traced down the guy who sold it to my friend and he also told me it came out of a sedan or wagon from 1995 but it should only be a 3,0 L. And with approx. 200 000 km on the clock. So this got me thinking, what is it that stands in my garage? Can I use it as it is and only change the oilpan? or should I take the turbo etc. and convert my original 300D (OM603) with only 140 000 km on it?

I took a closer look at the engine and couldn't find a plate which told me exactly what motor it is.
but I did find some numbers:
Engine block: 03B 95 and R 603 011 35 01
Dieselpump: 603 070 4701 ER 0045
A/C mount: R 6052340039
Alternatormount: R 603155 07 35
I belive "603" refers to OM603 series but can the numbers tell me more?

Thanks for answers

/P
Sweden