Yes, you're right, but the head tube lengths are short relative to size, which means the long-legged rider is going to struggle to get the handlebars to a comfortable height.

Taking the C-50 as an example. I'm usually looking for a top tube about 58cm:

(Size, TT, HT length)
60cm, 58 cm, 17.3 cm
61cm, 58.6 cm, 18.4 cm
62cm, 59 cm, 18.8 cm

Those are short head tubes relative to top tube.

In contrast, the Specialized Roubaix, size 58:
58, 58.2 cm, 22.5 cm

Or the Specialized Tarmac, size 58:
58, 58.2 cm, 20.5 cm

Or the BMC Pro Machine, size 59:
59, 58.5 cm, 20.4 cm

I suspect the Roubaix would fit me the best, and the Tarmac or Pro Machine would be fine. The Colnago, no way. And I'm not talking about Grant Petersen handle-bar-level-with-the-saddle fit, either...the Roubaix would still give me about 8cm saddle-bar drop.