I think it's safe to assume that there still exist 24-track, 2" masters from the recording sessions in England. If that is the case, all they have to do is remix those masters to stereo; put the brass on the left channel, the strings on the right channel, the MOOG here, percussion there. That's how you'd make a stereo recording in 2007 and no rearranging or reorchestration is needed.
In the original theme there is only one synthesized instrument: the MOOG. If Kalehoff does a complete "reorchestration" of the theme, it is conceivable that all of the instruments will be synthesized. If that happens, the theme will definitely lose its "soul". It will sound good, but it won't be the theme we're used to hearing. If we're lucky, he will keep many of the legacy instrumental parts: flugelhorn, tuba, glock, harp, trombones, etc.