@Miss Prism Here's the smokebox door of 6336 under flash illumination. It shows up differences in materials/finishes that you don't normally see:
Here's 6336 without flash:
Here's 6116 for comparison:
I measure the colour of the Mogul tender sides under a D50 illuminant as CIELAB = 22, -8, 4. (For comparison the Hornby Large Prairie 6116 is CIELAB = 25, -5, 7. So the Mogul is slightly darker, slightly greener, slightly less yellow than the Prairie.)
P.S. Correction to earlier statements: The smokebox door is not held in place by magnets - it's a simple friction fit.