The appeal and wearing characteristics of the older metal&glass Nikkors is legendary with their solid haptics and robustness. However there was discussion on this years back where the experienced photographers pointed out polycarbonate tends to absorb sudden shocks and impacts better than aluminum. I say this because 3 years ago I eventually found a Used 58 f1.4G in one of the surviving small camera shops near the British Museum in London. The owner explained he was only selling it to afford a new camera as he had dropped his D810 which was a write off, and this had been the lens he always used on the camera. And he assured me the lens was fine etc etc! I tested the lens as best I could in the circumstances and all seemed well.
To afford the unplanned purchase, the owner accepted a deposit but I only received the lens some months later - and on another continent. It was a shock to learn the bottom of the outer shell had a ~1'" hairline crack extending toward the mount from the inner edge of the focusing ring, so the 2 pieces flexed apart. The crack bisests the label 'Nano Crystal...'. So yes a hard lesson, as I should have scrutinized the carapace of this lens more carefully but was more concerned about dust/fungi and if the AF worked etc.
This damage also suggests the NeoNoct was more than an intimate witness of the camera's death.... A check on the www for a cross section of the Neo-Noct revealed the damage probably did not extend / had not been transmitted too deeply to dislodge the glass elements etc. I repaired the crack with industrial Epoxy. This sealed the opening and has halt the crack from spreading with use. All's been well since. It suggests polycarbonate has its positives but a sharp bash to the rim of a plastic lens often shears off the filter housing along the threads. In contrast, a metal filter housing tends to dent or bend inwards, which, if not too severe, can be repaired by skilled hands.