That photo does NOT have the same service parts a Sherwood or a Thermo valve overhaul kit. Similar, yes, as there is very little difference in most basic valve designs, but NOT the same. I highly recommend you do not use "looks close, maybe it will work, maybe with modifications" as your standard for servicing the valve parts.
Both Sherwood and Thermo specify a required overhaul at 5 year intervals, including the seat plug assembly and the complete burst disk assembly (if that applies in your region). Shorter intervals are fine with cleaning, lubricating, and inspecting - although the copper crush gasket requires replacement any time the valve is broken down, and the burst disk needs replacement any time it is removed. That is the scoop for those two manufacturers, and I have included links to their service manuals so you can read for yourself.
https://www.frogkick.dk/manuals/sherwood/Cylinder Valves.pdf
https://www.frogkick.dk/manuals/thermo-valve/thermo_valve_service_manual.pdf
Now, your valve was made by someone else, and I don't know who the actual OEM was or what other brands are interchangeable. But NOT Sherwood or Thermo, although I suspect the service interval recommendations will be the same once you can track them down. Why anyone would want to wait for their valve to give them trouble before replacing the seat and the burst disk is beyond me. How much $$ do you really save by skipping that at the prescribed 5 year service interval, versus the cost of possibly missing a dive or two (or more) when it finally does start to leak?
