Where did my whatchamacallit go?

That piece of the console that slides with the shifter and blocks the hole around it disappeared. What is it called and where might I find it. 66 Barracuda, automatic floor console.

All the little things are starting to eat at me with this new upholstery job. I have no recourse either, they closed up shop and had to use my facilities to finish the job then left town. I have screws in the wrong holes, missing weather stripping etc....

Sorry for whining.