It all boils down to PEOPLE, which I believe has been well stated here.
There are some builders who profess to specialize in restoration. But again, the individual shapers are key.
Rarely is there a 100% pure renovation. Nearly all "renovation" work involves new elements (tees, etc.), adjustments (shifts and change), mitigation (overcoming tree maturity, removal of trees, etc.) and re-building of features — perhaps lost to time, wear or neglect.
For these reasons, the golf architect is many times more essential to the process. He or she will orchestrate the vision. I have seen nearly clueless grounds crews rebuild a bunker and "get it right" when guided by an capable golf course architect. Many, if not all, of this crew had never seen a bunker built nor had ever considered what goes into the building of a sand hazard.