Cars and Watches have a similar dial, wrapped into a gold case, for a reasonable price in their portfolio. Pretty nice and uncommmon dial. https://www.carsandwatches.com/watches/longines-tank-watch-with-rare-enamel-dial
Wow, It sure cleaned up very nicely. For the record here are the pics from Cars and Watches. I must say I prefer the dial on the steel example. Interesting they are both from Spain and invoiced one year apart. Also including the description with dimensions.