Yes, that's all correct. To expand a little bit...
The 59 is a 1st Gen, made from around 1970 to 1982. Blued slide on a black aluminum frame. Rear sight is windage adjustable only and there is no firing pin lock so the pistol is not drop safe.
The 559 is a 2nd Gen pistol, it does have a passive firing pin safety and is drop safe. A 559 will most likely have an ambidextrous thumb decock lever where the 59 does not. The 559 has a heavy, full steel frame. And the rear sight will either be a dovetailed drift-adjustable (fixed) sight or the more common heavily protected adjustable rear sight.
The 2nd Gen pistols were only made for 6-7 years and in FAR fewer volume than either the 1st or 3rd Gen pistols. And in addition to that, the 559 is a somewhat rare pistol with the bright stainless 659 being more common.
If everything else is otherwise equal (never is!), it's an easy argument that a 559 is a more "valuable" and arguably better pistol. I myself would definitely choose the 559 over a 59.
