Difference between a 380S and upgraded 38 to 380S?

I am looking for information on what the differences are between an original Levinson 380S and a Levinson 38 that has been upgraded to a 380S? It was a factory authorized update. Thanks.
I can't claim 100% certainty about this (my 380S is a factory original), but I don't believe there's any difference at all. I can vouch that the 380S is a better-sounding preamp though. Why not ask the company directly if you're in doubt?