I think the early version (K0-K1) with indicator lamps within the clocks would not be compatible ie, cable length & wiring differences.
The later version (K2 onwards, 'dashboard' model) would be the best option. As you mentioned the lighting legend configuration did change a number of times with the 'dashboard' model, but providing the indicator lamps are fitted to the correct legend, then I do not see a problem.
As 'Trigger' mentioned 323 is a CB500 part reference. I think this particular part would also fit the CB750 K2 onwards.