Thanks for the replies! Due to the unexpected retirement of the household breadwinner (my wife), the budget for getting this project on the road is significantly constrained...
But, as a result of looking at John's results and following Dan's links, I think I have decided on a way forward.
Painting the bezel should be straight forward enough.
The Filling Station has a screen printed glass for that speedometer for $29.95, so that gives me the confidence to proceed carefully, with an attempt to clean the glass that I have. The Filling Station also has a dash decal set for $14.95 and a bezel gasket for $5.55.
The only hesitation I have now about doing an interim cleanup and reinstall is that the tabs on the bezel don't seem as though they would stand too much more flexing.
Nick 1940 KC Model 1/2 Ton Pickup Project (with '37-'39 Bed and what we think is a '42-'46 Frame) Taos, New Mexico