I believe that the list price for LEDs on a new instrument was something like $870 at the time this was quoted, so it wasn't a huge upcharge then for the after-market installation. I suppose it matters what sort of instrument you're retrofitting as well. For example, a series instrument might not need the battery cavity if the LEDs were to be powered from the 5-pin. It probably also matters what sort of backplate will cover the new battery compartment. Contnuous wood might not even be possible at this point, or at least would be difficult. Any kind of plating over brass would probably factor into the cost as well.
Dave's advice is sound, as always. Get yourself a quote from Valentino if you're really interested. That will take all of the variables into consideration.
