I think I'm missing a nut.

I would just leave the inner pulley on since you might want AC some day. To remove it, you must pull off the damper (middle pulley), which could cause problems. If you do remove it, sell it since rare. My 1964 didn't have one so bought an inner pulley from a member here. Took me a while to figure how it must fit. It has a large central hole to fit over the snout of the timing cover.

My engine also didn't have a center bolt, which confused me since I recalled a crank bolt on my 1969 slant. After cleaning all the gunk, I found the tapped hole. Bought a crank bolt and washer for it, I recall same PN as on 426 Hemi engines.