OK to put a 4x4 wood sleeve made from pressure treated material over the steel post in place of the white plastic pieces, to match other wood posts?

Hello Boop, If we are understanding your question correctly, you want to remove some of the white plastic pieces of the posts, correct? We would not encourage you to do this as the deck post has not necessarily been tested with components missing. Please email us again with your question phrased differently if we misinterpreted what you were asking. Thank you. Your Deckorators Team