1. Correct - a 59 series pistol will have a fatter perceived grip than a 439.
2. Later 439s and 639s had an ambi safety lever.
3. Correct
4. The 3904/3906 pistols have an ambi safety lever which you do not like. They are rather difficult to find but well worth the search.
I paid $500 for a LNIB 639 a few years ago.
