Any serious rust and the very high mleage might bother me.

Otherwise, first check with your insurance carrier Some won't insure a grey-market vehicle.

If that works out, make sure the seller's title VIN matches the one on the vehicle, including the WDB prefix. Especially if your seller is out of state.
I had this problem when purchasing my Euro 5-speed'84 TD a few years ago because, while the VINs matched, the missing WDB prefix on the Maryland title was rejected by Virginia DMV for insufficient characters - after 1980, the VIN is supposed to have at least 14 I believe.
Eventually this was resolved by myself and the seller going back to Maryland MVA to have an officer inspect the car's VIN and have a corrected Maryland title issued, which was accepted by Virginia DMV. But it was an extra hassle that took a couple weeks.

And recently, someone on this forum also reported problems trying to register an older Mercedes with no VIN on the windsheild pillar. Typically, grey-market cars like mine only have the VIN on the radiator support and firewall. It wasn't a problem in Virginia, but some jurisdictions require a pre-inspection of the VIN on the actuall vehicle, and may require a VIN-tag visible on the pillar or dash before the car can be registered.

As far as your current TD donating parts, most likely the manual TD is non-turbo. Much will interchage. But some parts will be different, like the radiator, climate-control, oil-pan gasket, etc....

Happy Motoring, Mark

__________________
DrDKW