I would agree with ALL of Dwig's comments regarding all three lenses. The 55mm has simply had some of the "buckhorns" machined off,along with some of the aperture control ridge on the TOP----but on the D90, the CRITICAL clearance is not the AI-coupling ridge or the AI-indexing ledge on the lens--the critical clearance is on the bottom of the lens mounting area, at the 7 o'clock position, where the minimum aperture sensing tab is located on a D80 or D90,and many other cameras. The machinist who milled off the back of the aperrture ring on the 55mm lens might not have also removed adequate (if ANY) metal on the bottom of the aperture ring, since when the conversion was done is unsure, and the minimum aperture sensing tab was NOT use on NIkon bodies of the 1970s and 1980s....many, but not all, pre-AI Nikkors had what are now sometimes called "fat aperture rings", which can break off that plastic tab a 7 o'clock on the body...
The 45 GN has a factory Ai conversion, with a replacement aperture ring. And secondary aperture scale.
The 24/2 is an AiS...the minimum aperture in orange, the holes in the buckhorns, and the secondary Aperture Direct Readout aperture scale also in color, plus the rubber focusing ring and aperture ring style, plus Nikon familiarity, all put this as an Ai-S lens. EDIT: OOPS!!! I typed out a reply while still on page 1...I didn't realize this had already been answered.