You don't need a Dork Disk/Pie Plate if your shifting is precise, calibrated, and structured. I don't use Dork Disks on my good bikes. They are not needed. But on the bikes I lend out, or ride in uneven bouncy terrain where I am pushing my friction shifters to get that chain a dancing... yes I do have Dork Disks. For me it's a hard learned lesson...
As far as Dork Disks go yours is pretty nice looking. I would keep it...
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