VC's Reference numbers refer to the specific case design and the Chronograph Historiques model that you have origianally started out as a Ref. 47101. Very minor modifications to the case were made, which VC decided to designate /1, /2, /3, and it looks like when they got to /4...they decided to give it a totally new number, Ref. 47111.
It looks like youw watch was a transition piece that originally used the older designation, but then officially changed to the new ref. number. VC, throughout its history, has done this type of thing before.
Congratulations on a great watch, I like the tradiotonal style strap you have on it, which tapers more dramatically from the lugs to the buckle. Welcome to THL!