Summary: I think the 28-105 will cover you for closeups of 4" sculptures and travel. Your FA 43 can still be used if you want a very thin depth of field portrait. The money not spent on the 24-70 can be set aside for a true 1:1 macro if you test the 28-105 and sometimes need even more magnification.
The FA 43 is especially bad for macro because it has a large minimum focus distance. Minimum focus distance combined with focal length determines how much magnification you can get.
The K-1 sensor is 24mm tall, just under 1". With a true 1:1 macro a 1" subject can fill the height of a photo. If your smallest subject is 4" then you might only need 1:4 or 0.25x magnification.
Magnification values below are from
Pentax Lenses - Pentax Lens Reviews & Lens Database
FA43 Max. Magnification =
0.12x. The DFA 28-105 can go to
0.22x (nearly double what the FA 43 can do). The 24-70 comes in close at
0.20x.
For general purpose use and travel, I love the 28-105 because it's sharp, compact, with good colors and contrast. The 24-70 offers f2.8, but you already can get f1.9 with your FA 43 for low light or thin depth of field.