I did my bunks over the winter. I bought all new wood, carpet, SS staples, and SS hardware for the bunks. I got everything, including the carpet, at lowes. The old wood was in pretty bad shape, and I had to tear a lot of it up to get them off the trailer. Mine were bolted on with carriage bolts, so I have to chisel away a lot of the wood to get a wrench under the head of the bolts.
A lot of people say you should use monel staples and non pressure treated wood, but I went with pressure treated wood and stainless staples.