That seems pretty close to advertised numbers. My Special is registered with the DMV at 710 kg, so, very close to your verified weight. Also, I believe the official advertised weight of a Special is 1570 lbs (714 kg), so again, very close.
I find this a bit refreshing, as advertised weights can often be tweaked by the manufacturer to present favourable numbers. I would expect that the 1570 lbs advertised for the Special would be a car with no fuel in the tanks, spare tire and tool kit not onboard, etc. However, whenever anyone has their Europa weighed and reported back to this forum, the results are very close to factory advertised numbers, and often lower. [edit: On second thought, I see your car is a Type 54, which should be lighter than a Special, so, perhaps the weights are indeed tweaked a bit in original literature]