A full system is overkill at forty assets, most sites your size run a simple register instead: one row per machine with make, model, serial, and a link to the documentation. The register is the important part, not the storage. For the gaps in your paper archive, an online source fills them faster than writing to manufacturers, and ManualMachine https://manualmachine.com/ covers a wide range of industrial brands. Record the plate details for every machine now, while people who know the equipment are still there. That data is what disappears when someone retires, not the paperwork. For the older machines, ask the people who run them what they know before it goes into the register, that knowledge is not written down anywhere else.