The oil varnish on my Shen is not the same as whatever is coming on the current ones, as mine was purchased white and finished later, but I can say that the varnish has "dulled" over the years, although it can be polished right back like new. I just never bother, because I'm lazy and neglect my bass.

But I think oil varnishes in general get sort of softer and warmer looking as they age...