I have been having a time with getting my shifter panel to sit down flat and my attention went to the noise isolator down in the hole where the automatic shifter box is. My car is VIN 3937 and has the early style auto trans shifter handle. On that same parts diagram, it shows the VIN change point as 4837. I hadn't realized, but those early style cars aren't meant to have the noise isolator. Not from the factory anyway.

For reference, this is p/n 110184. It is a big hunk of molded rubber and is meant to drown out the noise from below (and heat) and keep it out of the cabin.

Why mine got me stumped as to its origin is that it isn't quite the same as what is shown on Houston's parts page. It has all the same features except the indentation portion that gives you room to fit the underside of the shifter plate in there with the PRND21 plastic piece sticking out below. Mine doesn't have that indentation.

Anyone ever seen one like this before? Factory production change? Prototype of some kind? My shifter plate still isn't sitting in well, so this wasn't the only issue, but it at least lets me put my shifter plate light bulb back in position.