Nice score! It certainly looks rebuildable as well. I did a short stint for a fire and safety equipment company in portland oregon. We inspected and recharged those and larger extinguishers. The boss was adamant about using dry nitrogen with the new powder for recharging. The one thing we noticed when they are in rigs, especially trucks, was the powder would compact and cake up from road vibrations settling it. The deal was to shake them up and tap them with a tool handle occasionally to keep the powder loose.