That is why I suggested the magnet test so you can find out. It's your bubble that I was hoping not to burst too, as it is your bike and BB. Still would be neat for you if it was, as people pay big money for those these days.. Anyway, a steel spindle makes more sense to have on a bike if you are not seriously into weight weenism with it......Specially if you might have similar power in your legs like Fignon...

Have fun with the bike and tell us how it rides when you get it on the road!
Chombi