You are most welcome. What did Mr. Jahanzaib has to say about the price of these cars? I have seen them advertised from 180k through 1M or so. Obviously the condition determines the price. Recently a friend of a friend, a person not known to me, bought a W115 in half decent condition for 450k. Hopefully that should put you in the general ball park.
Since these cars cannot be compared to your everyday corolla or suzuki, it is hard to put a "market" value on them. But I'll try.
Here is probably one of the finest W115 in the country: https://www.pakwheels.com/rides/1972-mercedes-benz-e-class-of-ykkocorp - probably not for sale.
Here are a few examples that were/are for sale:
Top condition: https://www.pakwheels.com/used-cars/mercedes-benz-e-class-1971-for-sale-in-karachi-925124
Half way decent: http://www.clasf.pk/mercedes-w115-in-lahore-573611/
Basket case: https://www.pakwheels.com/used-cars/mercedes-benz-other-1979-for-sale-in-peshawar-1062599 - just 80k gets you a shell. Wrong engine and running gear plus interior seems wrong but cant tell clearly. Certainly the door card is incorrect.
Based on the above it is clear that you will not go and pay 1M for a basket case car. The choice is yours. Try to find a knowledgeable person in your city and discuss your project with him.