Since no has responded, I'll take a stab at it.
Important question: What is driving you to acquire this vehicle? Is it your passion for American Muscle? Or your passion for classic/vintage? This is none of them so it must be some other factors pushing you to thinking about buying it. If it still had its V8 or V6 then it would be a different matter all together. You will be looking at a car in near original condition which will have some value.
Sincere advice: Stay away from this. Pakistani mechanics have waved their magic wand and altered it by fixing a diesel engine/transmission. In my book it now has zero value. Others may disagree. Present owner is getting rid of it - must be a reason why. Who is to say how sound was the engineering behind this alteration? Was the drive shaft length altered? If it was, then was it dynamically balanced after alteration? Probably not. Do all the instruments work? probably not because the speedo drive comes off the transmission which is now no longer there. Even if they managed to get it to work my bet is that it will not give an accurate reading. The original transmission was a column shift, What is this one? Column shift? Floor shift? If it is on the floor, then the tunnel has been cut to make an opening for the shifter. The PRNDSL gear positions are indicated in the clock above the column. Does the gear position indicator still work? Additionally, I am assuming that the rear axle is original. If so, then did anyone work out the the final drive ratio with respect to new transmission ratios and engine RPM? Were the engine foundations altered? If so did anyone work out if the new alterations will sustain the power, torque and vibrations of the new engine/transmission setup. Will the new foundations cause any cracks over time in the original chassis?
Hence my original comment of the car being of zero value.
But on the other hand if you really don't care about these things .... not everybody does, and you want to tinker with it on a daily basis go ahead and get it. How much to pay for it? Maybe 2 - 3 lacs? What to check for? in addition to all of the above, Rust!!