There was a conversion floating around, to use an aftermarket fuel filter from a diesel tractor (or something like that). The supposed advantage was that the filter was easier to change, and much cheaper, and had an element that supposedly had better characteristics (particle size) than the OEM setup.
So this does not mean that it's a veggie car.
The way to tell if it's a veggie car, would be if there was a secondary tank, and ESPECIALLY, some heating mechanism to heat the secondary fuel line. (usually, this is a diversion from the radiator, with some copper tube that will wrap around the fuel-line - you start the car on diesel, get it warmed up, and about 5 minutes later, you can switch-over to veggie-oil. I had a friend who converted his Mercedes like this).
