The older razors were, indeed, hot-punched. The reasons the holes are larger was due to the size of the punch required. Too thin and it wouldn't work. The heat would ruin it to quickly and it simply wouldn't be tough enough, so the smallest hole they could get with this method was about 3/32. That method is still used by forgers for horseshoes. Drilling steel wasn't a practical option at the time. As manufacturing got more sophisticated, drilling became the preferred method and most solingen razors had their pivot holes drilled for exact placement and consistency in size and angle.
