Welcome to the forum, jrwood. It's always great to hear about Speedies that have stayed in the family, for so many years.
Wytnucls mentioned a white dialed "Apollo" Speedmaster, which I'm guessing is similar to this model.
Apologies, but I cannot recall where I acquired this photo.
I've seen it described as a prototype, but also as a very limited release.
However, I'm guessing that you're referring to a standard dark dialed Speedy. Over the years, I've seen some early models with red chrono second hands. Some, with a straight/slab-type hand, like this,
and others with a red standard Speedy hand, like the one on the white Speedy, above. I strongly suspect that the straight/slab-style hands are replacements, but, admittedly, I long suspected that the standard-style red second hands were either custom painted, or replacements. As you've noted you are certain that your father's is original, it would seem that a few left the factory this way. This is very interesting to note.
If you are able, we'd love to see photos!
eric