I now understand what you meant by the hole in the column. I of course learned the hard way by installing the column twice. For those who don't want to do that, here's a picture with all the key items that should line up.
From left to right, the hole in the column, keeper pin in coupler, dent in coupler, keyed spot in the spline. If I've got it wrong again, I'll be sad but please let me know.