Thanks Ross! This confirms what I was just thinking. It occurred to me after my previous post that the problem may be that I was trying to force the screw holes to line-up. The package tray and side shields were from different cars and I'm trying to fit them into a third one. I wouldn't be surprised if, on the assembly line, there were only holes in the side shields and they used the screws to drill holes into the package tray however they wound-up aligning.
Oh, they were missing from the parts car, since I took those pictures before tearing anything apart, otherwise I would've grabbed them. My car did not have trim there with original back seat because the flat fiberboard package tray went right to the edge of the headliner and was high enough to cover the unfinished edge of the headliner.
Perhaps. I'll have to look in the parts book to find the part numbers. Meanwhile, I may have found a plan-B. Joe gave me a box of misc chrome pieces after he sold his convertible. I thought I remembered seeing some that might be what I'm looking for. I found them. They're close to the correct shape but too long, and the angle is wrong at the front.
Being this far along in reassembly, I'm not keen on removing the window trim again to lift the headliner. I'm sure that the marks I made from aligning the trim against the C-pillars are close to the correct locations, and the trim will cover a large section of headliner once installed. I think I'll cut some small X marks in the headliner at the approximate screw locations, peel it back and look for dimples to indicate exactly where to drill. If I don't see any, I'll drill at the spots which I marked.
