Belg,
No, for N scale, that's .5 oz plus .15 oz per inch. So if you could find a 1" car it should weigh in at .65 oz. A 4" car would be1.1 oz
David,
On a N scale, I could get four or five glued-together nails across a car. If you look at the picture, I have a strips of 1 1/2" and 1" brads as they come glued together. On say an Atlas car I only needed a few nails, like a strip of four, on a Bachman or LL I sometimes had to add two or three strips (up to like 12-14 nails total), 1 1/2" long to get to the ideal weight. I sandwiched these strips with double-backed foam tape which basically added no weight. A few cars I had to go down to a 1" long size because longer ones wouldn't fit inside the car.
Don