In all honestly we are talking apples and oranges.
Not a great pic but this is is the shifter out of my 70 chevelle and a spare for my brothers 68 impala.
One rod the 1/2 is the same. Chevelle mounts to the cross member with the front tab to the right impala to the left, stablizer rods are different lengths and handles are different.
Handles impala/chevelle console then impala/ chevelle bench
Bare shifter with no mounting bracket and rods I think are the same but that is it.
That is why there is normally at least a 500.00 difference in price when you do see an impala complete shifter vs chevelle.
The reverse lock out set up for impala is in a class all of it's own and just about impossible to find complete.