Column shaft lower seal

Sorting out this 65 Barracuda that I bought site unseen. Super clean CA car. When I drove it home from where I met the shipper I noticed lots of hot air coming in around the bottom of the column. I found the large seal that seals the shaft around the column jacket in the engine compartment missing. This looks like a big job. I have a new seal - the one with the white nylon bushing in the center.

To install the seal I have to remove the column, remove the coupler, and remove the coupler shoe pin to be able to slide the new seal up the shaft, correct? Is there guidance on removing that coupler pin? Thank you.
i used one of these for a temp fix...https://images.homedepot-static.com...erbilt-escutcheons-flanges-c5340c-64_1000.jpg