The 105/1.4 appears to have an outer plastic shell similar to lenses like the AFS 85/1.4. Overall the size and weight is similar to lenses like the 135DC and AFS 24-70, so I expect a similar mix of materials in the constuction.
Roland,
I had the chance to handle it for a few minutes. A few things I memorized:
The 105mm/1.4 looks like and handles like a beefed-up AFS 85mm/1.4G. The difference is more tangible on the diameter, less on the length. With the hood, the length of the AFS 105mm/1.4 vs. the AFS 85mm/1.4G is about 4cm longer. The tactile feeling is very similar between the two lenses (on material, grip, buttons). The major differences on the tube are the golden characters "1.4G" vs. "1.4E ED", the inscription "M/A" and "M" and the white dot (finding the proper mounting position) is larger on the 105.
Dismounted, the AFS 85mm (a "G" lens) keeps the blades on the smallest aperture f16, the 105mm "E" keeps it open at f1.4. Looking through the front lens, there is a direct view on the inner imprint of the LF-1 "LF-1 Made in Japan".
While the weight is similar to the 135mm DC, the ratio diameter:length there is very different. Also the material.
With the AFS 24-70mm VR, the material seems to be more or less identical, but the "missing" diameter of the 24-70 creates a very different handling experience.
On a single digit body with the AFS 105mm, the combo handles "balanced".
BTW, it has 4+ screws (in your terminology), s/n is 7 digits.
rgds, Andy