AUGUSTA — Workers finished installing the State House dome’s new copper sheathing Wednesday soon after lawmakers approved a plan to use the century-old greenish copper removed from the dome for souvenirs and other artistic undertakings. The entire $1.3 million dome restoration project won’t be completed until late November, but the bulk of the work is done. The Legislative Council approved a plan crafted with the help of the Maine Arts Commission that calls for using portions of the roughly 6,500 square feet of copper to make commemorative souvenirs that will be sold to the public, selling some copper to jewelers or other artists, donating some to sculptors and reserving some to commission public art pieces using the copper. The remaining copper will be sold as scrap.