Equipment 'I.O.U.' plates for Scanning Electron Microscope

I'm reconditioning a Hitachi S4500 scanning electron microscope, and a lot of the detectors and accessories have been removed. Reattaching them properly requires loads of cleaning, baking at high temperatures and replacing consumable gaskets each time, which I'm not ready to do just yet.

I also want to check I've got all the parts sorted and the joints accounted for, but I don't want to leave the actual parts half-attached just in case it damages the flanges or o-rings.

Hence these piece