>showing the growth rings
I vote as David.
Though you didn't ask about leaving them square, or say you'd leave
them square: I would be tempted to knock the corners off the posts
(octogon shaped), ....
***depending on the dimensions of the bed's side rail ends that would
butt against the posts. A scrap piece of post, with corners cut off
(for a comparative view and face measurement), would probably assist
in the decision to cut or not.
***Another option is to leave square, only, the lower areas that the
side rails butt against.
***I also assume you already have a view and measurements, of some