Leonard Nimoy's actual uniform from TVH. Beginning with Wrath of Khan, the officers began to wear these dashing uniforms. This jacket has been specifically photo-matched to a series of Voyage Home PR shots. It also appears to match the version Nimoy wears on-screen.
In a key scene in the film, Spock dives into the whale tank and does a Vulcan mindmeld with the whale named Gracie. He first takes off his Vulcan robe and we see he has this undergarment on beneath it. Complete with Nimoy's hand-ripped headband.