That one does look to be in really rough shape, At a minimum it would need a couple seal change though out. First thing would be to find out if the company is still in business, second would be parts and operating manuals.
Unless you wanted a collector item, maybe I should say you need to find out if you can get the calcium carbide pellets locally and what rules and regulations that apply for use, storage and disposal.
Even if the waste material is neutralized, there may be test required, and it still might be classed as hazardous waste, with all fees, and permits. It has a salty taste, that animals love.
Another question is does it allow you to do a partial fill load.
Does it allow you to stop the process completely.
It would be a whole lot more hassles than buying a cylinder, and then exchanging it. If you are using it just for heating, bending, cutting and soldering or brazing. You may want to thing about propane or butane. What ever the formula and name for the heating and cooking bottle gas in your area.
Used with oxygen as a fuel gas, the only thing that you can't used it for is ferrous welding. As nothing but acetylene/oxy combination can achieve a true neutral flame. Keeping contamination of the welding puddle to a minimum.