Changing defroster vents on my 64 non-ac barracuda

I purchased new defroster vents for my 64 Barracuda. Pulled the driver's bucket seat out to make it easier (I'm 72) to get under the dashboard. Still couldn't reach up there with a socket and extension to get at the 3 thread cutting nuts. Do i have to remove the instrument cluster to get at the nuts?

What I ended up doing... got a little aggravate with the whole process. Just kidding..

Contact cement the nut into the socket so you don't have to deal with dropping it.

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