It does look suitably worn, though. Maybe 1920 is not a year but a vehicle number or even depot/works number?Some Johnson Midland Railway 0-6-0 3F locos from 1885 were rebuilt in 1920 with Belpaire fireboxes, presumably at Derby; might be off one of those? But why the LMS, not formed until 1922, would put a new plate on a loco rebuilt two years before, I am uncertain. I wonder if it's a more recent and inaccurate reproduction.......
It's the wear that makes me question this plate - it looks almost too worn and very unevenly as well. The few loco plates that I've seen have much more even wear because they were cleaned evenly. But I admit I'm not an expert on these and am quite prepared to be corrected!It does look suitably worn, though. Maybe 1920 is not a year but a vehicle number or even depot/works number?