The AC units are not the same size. Because of this, the endcaps are different THICKNESSES so they will come up flush with the AC unit. The console is cut at the same place, so to "close" the gap, one endcap is much thicker than the other. There is a part number on the underside, a C5 for 65 and a C6 for a 66. I have both of them, I think, at home on a shelf, and can take a picture, if needed.
BTW, the 65 is reproduced a LOT cheaper than the 66. Do not know why, just the way it is.