If it was written after the car was painted, there wouldn't be any trace of it once the car was blasted. It would have been written before paint. It sounds plausible that it meant 26" radiator but there is no way to know for sure. My floor pan had a large three digit number written on it from the factory. There is no way to know for sure what it stood for. My guess is that it was the top part in a stack of floor pans. Maybe the last three digits of the part #?