Would early 60's Jazzmasters and Jaguars have any kind of undercoat to their finish? In particular, something like a white undercoat to a blonde finish. I've seen some finishes that look like refin's but obviously the dealers claim the finish is original and it's just the "undercoat" showing through. I've never read or heard about undercoats before and would like to know if there is any validity to it. Thanks.