I think this is the GTO/etc hump that covers the Hurst shifter... As mentioned, it is NOT correct for a Chevelle, but should work (with GTO carpet) if you wanted to clear a Hurst shifter... Beware, there are still a LOT of sellers that say this is correct "Chevelle" non-console...
This is the "correct" hump for a 64-67 Chevelle Manual floor-shift transmission
Here's the correct boot for all 64-67 floor-shifted manual trans cars.
Here's the "carpet ring"
The boot and retainer screw to the floor, beneath the carpet, and the carpet ring dresses up the hole cut in the carpet...
Here's is what the finished assembly looks like, correct for any 64-66 Chevelle/El Camino:
Note that ALL 64-66 Chevelles will use the same setup, bench or buckets, console or not console (not all bucket seat cars came with consoles)...
Here is the '67 Chrome hump for the bench seat cars, but IIRC, the floor still uses the oval hump and boot, as this chrome piece is just decorative, on to of the carpet.
While not correct for a 64-66 benchseat car, it should fit and look okay.
The floor pans were basically the same for all 64-67 Chevelles (including El Camino, Wagon, hardtop, convertible and 4-door), so the humps parts should all fit (no guarantee of repro parts fitting perfectly though)