That’s Ok. I just felt obligated so that 20 years from now you’re not kicking yourself when they are very valuable (if they aren’t already). If you don’t need the money then I’d suggest sitting on it for a while. You’d be surprised how us bike nerds change over time.
If you are prepared to move it I’m sure there might be a few people locally who are interested if you can put a value on it. Alternately, I’d also suggest trading it for something’s you’re more interested in.
My last piece of advice is to sell it to Blakey for $300
The headclip is a leftover from older style headset systems. It’s hard to know exactly what Cinelli uses here but often the steerer is slotted in a “t” section which allows the headclip to compress and hold onto the steerer. Important to have the stem in place before tightening (but that should be case with any threaded headset anyway). These parts can be fiddly to set up, hard to find and I’m not sure why they were still in use for bikes of this era.
Maybe they just didn’t trust spacer washers (shrugs shoulders)? Or maybe they thought that headset adjutsment was too hit and miss and liked the security of a headclip clamping directly to the steerer, thus using less reliance on the top nut to hold it all together.