I reckon it's a 300tdi
We shall see if the chassis number exists with no welding in that area.
Maybe the OP can provide a photo of the chassis number stamped on the chassis.
Just so you know, if you didn't already, they never made a 1989 300tdi.
Post the advert and check it has a vin number relevant to the vehicle.
It is highly likely it will have rust, you just have to find it.
That would polish up pretty good I should think, good enough anyway.
Where would you stop though?
Once the bodywork is done, then it's the interior, then the engine etc
There are different pads and pins for 110, you need the others by the sounds of it.
Along with calipers and discs.
I had the same problem with my 90 which has 110 brakes on the back.
Essentially one set of pads are thicker, the later ones I think...
With no number plate, no v5, no stamped chassis number and no chassis plate then I'm afraid it's only really a collection of parts.
Some tdi and some series 2 and series 3.